Birchfield v. N. Dakota. William Robert Bernard

(Slip Opinion) OCTOBER TERM, 2015 1

Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
being done in connection with this case, at the time the opinion is issued.
The syllabus constitutes no part of the opinion of the Court but has been
prepared by the Reporter of Decisions for the convenience of the reader.
See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

BIRCHFIELD v. NORTH DAKOTA

CERTIORARI TO THE SUPREME COURT OF NORTH DAKOTA

No. 14–1468. Argued April 20, 2016—Decided June 23, 2016*
To fight the serious harms inflicted by drunk drivers, all States have
laws that prohibit motorists from driving with a blood alcohol concen-
tration (BAC) exceeding a specified level. BAC is typically deter-
mined through a direct analysis of a blood sample or by using a ma-
chine to measure the amount of alcohol in a person’s breath. To help
secure drivers’ cooperation with such testing, the States have also
enacted “implied consent” laws that require drivers to submit to BAC
tests. Originally, the penalty for refusing a test was suspension of
the motorist’s license. Over time, however, States have toughened
their drunk-driving laws, imposing harsher penalties on recidivists
and drivers with particularly high BAC levels. Because motorists
who fear these increased punishments have strong incentives to re-
ject testing, some States, including North Dakota and Minnesota,
now make it a crime to refuse to undergo testing.
In these cases, all three petitioners were arrested on drunk-driving
charges. The state trooper who arrested petitioner Danny Birchfield
advised him of his obligation under North Dakota law to undergo
BAC testing and told him, as state law requires, that refusing to
submit to a blood test could lead to criminal punishment. Birchfield
refused to let his blood be drawn and was charged with a misde-
meanor violation of the refusal statute. He entered a conditional
guilty plea but argued that the Fourth Amendment prohibited crimi-
nalizing his refusal to submit to the test. The State District Court re-
——————
* Together with No. 14–1470, Bernard v. Minnesota, on certiorari to
the Supreme Court of Minnesota, and No. 14–1507, Beylund v. Levi,
Director, North Dakota Department of Transportation, also on certiorari
to the Supreme Court of North Dakota.
2 BIRCHFIELD v. NORTH DAKOTA

Syllabus

jected his argument, and the State Supreme Court affirmed.
After arresting petitioner William Robert Bernard, Jr., Minnesota
police transported him to the station. There, officers read him Min-
nesota’s implied consent advisory, which like North Dakota’s informs
motorists that it is a crime to refuse to submit to a BAC test. Ber-
nard refused to take a breath test and was charged with test refusal
in the first degree. The Minnesota District Court dismissed the
charges, concluding that the warrantless breath test was not permit-
ted under the Fourth Amendment. The State Court of Appeals re-
versed, and the State Supreme Court affirmed.
The officer who arrested petitioner Steve Michael Beylund took
him to a nearby hospital. The officer read him North Dakota’s im-
plied consent advisory, informing him that test refusal in these cir-
cumstances is itself a crime. Beylund agreed to have his blood
drawn. The test revealed a BAC level more than three times the le-
gal limit. Beylund’s license was suspended for two years after an
administrative hearing, and on appeal, the State District Court re-
jected his argument that his consent to the blood test was coerced by
the officer’s warning. The State Supreme Court affirmed.
Held:
1. The Fourth Amendment permits warrantless breath tests inci-
dent to arrests for drunk driving but not warrantless blood tests.
Pp. 13–36.
(a) Taking a blood sample or administering a breath test is a
search governed by the Fourth Amendment. See Skinner v. Railway
Labor Executives’ Assn., 489 U. S. 602, 616–617; Schmerber v. Cali-
fornia, 384 U. S. 757, 767–768. These searches may nevertheless be
exempt from the warrant requirement if they fall within, as relevant
here, the exception for searches conducted incident to a lawful arrest.
This exception applies categorically, rather than on a case-by-case
basis. Missouri v. McNeely, 569 U. S. ___, ___, n. 3. Pp. 14–16.
(b) The search-incident-to-arrest doctrine has an ancient pedi-
gree that predates the Nation’s founding, and no historical evidence
suggests that the Fourth Amendment altered the permissible bounds
of arrestee searches. The mere “fact of the lawful arrest” justifies “a
full search of the person.” United States v. Robinson, 414 U. S. 218,
235. The doctrine may also apply in situations that could not have
been envisioned when the Fourth Amendment was adopted. In Riley
v. California, 573 U. S. ___, the Court considered how to apply the
doctrine to searches of an arrestee’s cell phone. Because founding era
guidance was lacking, the Court determined “whether to exempt [the]
search from the warrant requirement ‘by assessing, on the one hand,
the degree to which it intrudes upon an individual’s privacy and, on
the other, the degree to which it is needed for the promotion of legit-
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Syllabus

imate governmental interests.’ ” Id., at ___. The same mode of anal-
ysis is proper here because the founding era provides no definitive
guidance on whether blood and breath tests should be allowed inci-
dent to arrest. Pp. 16–20.
(c) The analysis begins by considering the impact of breath and
blood tests on individual privacy interests. Pp. 20–23.
(1) Breath tests do not “implicat[e] significant privacy con-
cerns.” Skinner, 489 U. S., at 626. The physical intrusion is almost
negligible. The tests “do not require piercing the skin” and entail “a
minimum of inconvenience.” Id., at 625. Requiring an arrestee to in-
sert the machine’s mouthpiece into his or her mouth and to exhale
“deep lung” air is no more intrusive than collecting a DNA sample by
rubbing a swab on the inside of a person’s cheek, Maryland v. King,
569 U. S. ___, ___, or scraping underneath a suspect’s fingernails,
Cupp v. Murphy, 412 U. S. 291. Breath tests, unlike DNA samples,
also yield only a BAC reading and leave no biological sample in the
government’s possession. Finally, participation in a breath test is not
likely to enhance the embarrassment inherent in any arrest. Pp. 20–
22.
(2) The same cannot be said about blood tests. They “require
piercing the skin” and extract a part of the subject’s body, Skinner,
supra, at 625, and thus are significantly more intrusive than blowing
into a tube. A blood test also gives law enforcement a sample that
can be preserved and from which it is possible to extract information
beyond a simple BAC reading. That prospect could cause anxiety for
the person tested. Pp. 22–23.
(d) The analysis next turns to the States’ asserted need to obtain
BAC readings. Pp. 23–33.
(1) The States and the Federal Government have a “paramount
interest . . . in preserving [public highway] safety,” Mackey v.
Montrym, 443 U. S. 1, 17; and States have a compelling interest in
creating “deterrent[s] to drunken driving,” a leading cause of traffic
fatalities and injuries, id., at 18. Sanctions for refusing to take a
BAC test were increased because consequences like license suspen-
sion were no longer adequate to persuade the most dangerous offend-
ers to agree to a test that could lead to severe criminal sanctions. By
making it a crime to refuse to submit to a BAC test, the laws at issue
provide an incentive to cooperate and thus serve a very important
function. Pp. 23–25.
(2) As for other ways to combat drunk driving, this Court’s de-
cisions establish that an arresting officer is not obligated to obtain a
warrant before conducting a search incident to arrest simply because
there might be adequate time in the particular circumstances to ob-
tain a warrant. The legality of a search incident to arrest must be
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judged on the basis of categorical rules. See e.g., Robinson, supra, at
235. McNeely, supra, at ___, distinguished. Imposition of a warrant
requirement for every BAC test would likely swamp courts, given the
enormous number of drunk-driving arrests, with little corresponding
benefit. And other alternatives—e.g., sobriety checkpoints and igni-
tion interlock systems—are poor substitutes. Pp. 25–30.
(3) Bernard argues that warrantless BAC testing cannot be
justified as a search incident to arrest because that doctrine aims to
prevent the arrestee from destroying evidence, while the loss of blood
alcohol evidence results from the body’s metabolism of alcohol, a nat-
ural process not controlled by the arrestee. In both instances, howev-
er, the State is justifiably concerned that evidence may be lost. The
State’s general interest in “evidence preservation” or avoiding “the
loss of evidence,” Riley, supra, at ___, readily encompasses the me-
tabolization of alcohol in the blood. Bernard’s view finds no support
in Chimel v. California, 395 U. S. 752, 763, Schmerber, 384 U. S., at
769, or McNeely, supra, at ___. Pp. 30–33.
(e) Because the impact of breath tests on privacy is slight, and
the need for BAC testing is great, the Fourth Amendment permits
warrantless breath tests incident to arrests for drunk driving. Blood
tests, however, are significantly more intrusive, and their reasona-
bleness must be judged in light of the availability of the less invasive
alternative of a breath test. Respondents have offered no satisfactory
justification for demanding the more intrusive alternative without a
warrant. In instances where blood tests might be preferable—e.g.,
where substances other than alcohol impair the driver’s ability to op-
erate a car safely, or where the subject is unconscious—nothing pre-
vents the police from seeking a warrant or from relying on the exi-
gent circumstances exception if it applies. Because breath tests are
significantly less intrusive than blood tests and in most cases amply
serve law enforcement interests, a breath test, but not a blood test,
may be administered as a search incident to a lawful arrest for drunk
driving. No warrant is needed in this situation. Pp. 33–35.
2. Motorists may not be criminally punished for refusing to submit
to a blood test based on legally implied consent to submit to them. It
is one thing to approve implied-consent laws that impose civil penal-
ties and evidentiary consequences on motorists who refuse to comply,
but quite another for a State to insist upon an intrusive blood test
and then to impose criminal penalties on refusal to submit. There
must be a limit to the consequences to which motorists may be
deemed to have consented by virtue of a decision to drive on public
roads. Pp. 36–37.
3. These legal conclusions resolve the three present cases. Birch-
field was criminally prosecuted for refusing a warrantless blood
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Syllabus

draw, and therefore the search that he refused cannot be justified as
a search incident to his arrest or on the basis of implied consent. Be-
cause there appears to be no other basis for a warrantless test of
Birchfield’s blood, he was threatened with an unlawful search and
unlawfully convicted for refusing that search. Bernard was criminal-
ly prosecuted for refusing a warrantless breath test. Because that
test was a permissible search incident to his arrest for drunk driving,
the Fourth Amendment did not require officers to obtain a warrant
prior to demanding the test, and Bernard had no right to refuse it.
Beylund submitted to a blood test after police told him that the law
required his submission. The North Dakota Supreme Court, which
based its conclusion that Beylund’s consent was voluntary on the er-
roneous assumption that the State could compel blood tests, should
reevaluate Beylund’s consent in light of the partial inaccuracy of the
officer’s advisory. Pp. 37–38.
No. 14–1468, 2015 ND 6, 858 N. W. 2d 302, reversed and remanded;
No. 14–1470, 859 N. W. 2d 762, affirmed; No. 14–1507, 2015 ND 18,
859 N. W. 2d 403, vacated and remanded.

ALITO, J., delivered the opinion of the Court, in which ROBERTS, C. J,
and KENNEDY, BREYER, and KAGAN, JJ., joined. SOTOMAYOR, J., filed an
opinion concurring in part and dissenting in part, in which GINSBURG,
J., joined. THOMAS, J., filed an opinion concurring in the judgment in
part and dissenting in part.
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Opinion of the Court

NOTICE: This opinion is subject to formal revision before publication in the
preliminary print of the United States Reports. Readers are requested to
notify the Reporter of Decisions, Supreme Court of the United States, Wash­
ington, D. C. 20543, of any typographical or other formal errors, in order
that corrections may be made before the preliminary print goes to press.

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 14–1468, 14–1470, and 14–1507
_________________

DANNY BIRCHFIELD, PETITIONER
14–1468 v.
NORTH DAKOTA;
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

NORTH DAKOTA

WILLIAM ROBERT BERNARD, JR., PETITIONER
14–1470 v.
MINNESOTA; AND
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

MINNESOTA

STEVE MICHAEL BEYLUND, PETITIONER
14–1507 v.
GRANT LEVI, DIRECTOR, NORTH DAKOTA
DEPARTMENT OF TRANSPORTATION
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

NORTH DAKOTA

[June 23, 2016]

JUSTICE ALITO delivered the opinion of the Court.
Drunk drivers take a grisly toll on the Nation’s roads,
claiming thousands of lives, injuring many more victims,
and inflicting billions of dollars in property damage every
2 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

year. To fight this problem, all States have laws that
prohibit motorists from driving with a blood alcohol con­
centration (BAC) that exceeds a specified level. But de­
termining whether a driver’s BAC is over the legal limit
requires a test, and many drivers stopped on suspicion of
drunk driving would not submit to testing if given the
option. So every State also has long had what are termed
“implied consent laws.” These laws impose penalties on
motorists who refuse to undergo testing when there is
sufficient reason to believe they are violating the State’s
drunk-driving laws.
In the past, the typical penalty for noncompliance was
suspension or revocation of the motorist’s license. The
cases now before us involve laws that go beyond that and
make it a crime for a motorist to refuse to be tested after
being lawfully arrested for driving while impaired. The
question presented is whether such laws violate the
Fourth Amendment’s prohibition against unreasonable
searches.
I
The problem of drunk driving arose almost as soon as
motor vehicles came into use. See J. Jacobs, Drunk Driv­
ing: An American Dilemma 57 (1989) (Jacobs). New Jer­
sey enacted what was perhaps the Nation’s first drunk-
driving law in 1906, 1906 N. J. Laws pp. 186, 196, and
other States soon followed. These early laws made it
illegal to drive while intoxicated but did not provide a
statistical definition of intoxication. As a result, prosecu­
tors normally had to present testimony that the defendant
was showing outward signs of intoxication, like imbalance
or slurred speech. R. Donigan, Chemical Tests and the
Law 2 (1966) (Donigan). As one early case put it, “[t]he
effects resulting from the drinking of intoxicating liquors
are manifested in various ways, and before any one can be
shown to be under the influence of intoxicating liquor it is
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Opinion of the Court

necessary for some witness to prove that some one or more
of these effects were perceptible to him.” State v. Noble,
119 Ore. 674, 677, 250 P. 833, 834 (1926).
The 1930’s saw a continued rise in the number of motor
vehicles on the roads, an end to Prohibition, and not coin­
cidentally an increased interest in combating the growing
problem of drunk driving. Jones, Measuring Alcohol in
Blood and Breath for Forensic Purposes—A Historical
Review, 8 For. Sci. Rev. 13, 20, 33 (1996) (Jones). The
American Medical Association and the National Safety
Council set up committees to study the problem and ulti­
mately concluded that a driver with a BAC of 0.15% or
higher could be presumed to be inebriated. Donigan 21–
22. In 1939, Indiana enacted the first law that defined
presumptive intoxication based on BAC levels, using the
recommended 0.15% standard. 1939 Ind. Acts p. 309;
Jones 21. Other States soon followed and then, in re­
sponse to updated guidance from national organizations,
lowered the presumption to a BAC level of 0.10%. Don­
igan 22–23. Later, States moved away from mere pre­
sumptions that defendants might rebut, and adopted laws
providing that driving with a 0.10% BAC or higher was
per se illegal. Jacobs 69–70.
Enforcement of laws of this type obviously requires the
measurement of BAC. One way of doing this is to analyze
a sample of a driver’s blood directly. A technician with
medical training uses a syringe to draw a blood sample
from the veins of the subject, who must remain still during
the procedure, and then the sample is shipped to a sepa­
rate laboratory for measurement of its alcohol concentra­
tion. See 2 R. Erwin, Defense of Drunk Driving Cases
§§17.03–17.04 (3d ed. 2015) (Erwin). Although it is possi­
ble for a subject to be forcibly immobilized so that a sam­
ple may be drawn, many States prohibit drawing blood
from a driver who resists since this practice helps “to
avoid violent confrontations.” South Dakota v. Neville,
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459 U. S. 553, 559 (1983).
The most common and economical method of calculating
BAC is by means of a machine that measures the amount
of alcohol in a person’s breath. National Highway Traffic
Safety Admin. (NHTSA), E. Haire, W. Leaf, D. Preusser, &
M. Solomon, Use of Warrants to Reduce Breath Test Re­
fusals: Experiences from North Carolina 1 (No. 811461,
Apr. 2011). One such device, called the “Drunkometer,”
was invented and first sold in the 1930’s. Note, 30 N. C.
L. Rev. 302, 303, and n. 10 (1952). The test subject would
inflate a small balloon, and then the test analyst would
release this captured breath into the machine, which
forced it through a chemical solution that reacted to the
presence of alcohol by changing color. Id., at 303. The test
analyst could observe the amount of breath required to
produce the color change and calculate the subject’s breath
alcohol concentration and by extension, BAC, from this
figure. Id., at 303–304. A more practical machine, called
the “Breathalyzer,” came into common use beginning in
the 1950’s, relying on the same basic scientific principles.
3 Erwin §22.01, at 22–3; Jones 34.
Over time, improved breath test machines were devel­
oped. Today, such devices can detect the presence of
alcohol more quickly and accurately than before, typically
using infrared technology rather than a chemical reaction.
2 Erwin §18A.01; Jones 36. And in practice all breath
testing machines used for evidentiary purposes must be
approved by the National Highway Traffic Safety Admin­
istration. See 1 H. Cohen & J. Green, Apprehending and
Prosecuting the Drunk Driver §7.04[7] (LexisNexis 2015).
These machines are generally regarded as very reliable
because the federal standards require that the devices
produce accurate and reproducible test results at a variety
of BAC levels, from the very low to the very high. 77 Fed.
Reg. 35747 (2012); 2 Erwin §18.07; Jones 38; see also
California v. Trombetta, 467 U. S. 479, 489 (1984).
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Opinion of the Court

Measurement of BAC based on a breath test requires
the cooperation of the person being tested. The subject
must take a deep breath and exhale through a mouthpiece
that connects to the machine. Berger, How Does it Work?
Alcohol Breath Testing, 325 British Medical J. 1403 (2002)
(Berger). Typically the test subject must blow air into the
device “ ‘for a period of several seconds’ ” to produce an
adequate breath sample, and the process is sometimes
repeated so that analysts can compare multiple samples to
ensure the device’s accuracy. Trombetta, supra, at 481;
see also 2 Erwin §21.04[2][b](L), at 21–14 (describing the
Intoxilyzer 4011 device as requiring a 12-second exhala­
tion, although the subject may take a new breath about
halfway through).
Modern breath test machines are designed to capture
so-called “deep lung” or alveolar air. Trombetta, supra, at
481. Air from the alveolar region of the lungs provides the
best basis for determining the test subject’s BAC, for it is
in that part of the lungs that alcohol vapor and other
gases are exchanged between blood and breath. 2 Erwin
§18.01[2][a], at 18–7.
When a standard infrared device is used, the whole
process takes only a few minutes from start to finish.
Berger 1403; 2 Erwin §18A.03[2], at 18A–14. Most evi­
dentiary breath tests do not occur next to the vehicle, at
the side of the road, but in a police station, where the
controlled environment is especially conducive to reliable
testing, or in some cases in the officer’s patrol vehicle or in
special mobile testing facilities. NHTSA, A. Berning et al.,
Refusal of Intoxication Testing: A Report to Congress 4,
and n. 5 (No. 811098, Sept. 2008).
Because the cooperation of the test subject is necessary
when a breath test is administered and highly preferable
when a blood sample is taken, the enactment of laws
defining intoxication based on BAC made it necessary for
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Opinion of the Court

States to find a way of securing such cooperation.1 So-
called “implied consent” laws were enacted to achieve this
result. They provided that cooperation with BAC testing
was a condition of the privilege of driving on state roads
and that the privilege would be rescinded if a suspected
drunk driver refused to honor that condition. Donigan
177. The first such law was enacted by New York in 1953,
and many other States followed suit not long thereafter.
Id., at 177–179. In 1962, the Uniform Vehicle Code also
included such a provision. Id., at 179. Today, “all 50
States have adopted implied consent laws that require
motorists, as a condition of operating a motor vehicle
within the State, to consent to BAC testing if they are
arrested or otherwise detained on suspicion of a drunk-
driving offense.” Missouri v. McNeely, 569 U. S. ___, ___
(2013) (plurality opinion) (slip op., at 18). Suspension or
revocation of the motorist’s driver’s license remains the
standard legal consequence of refusal. In addition, evi­
dence of the motorist’s refusal is admitted as evidence of
likely intoxication in a drunk-driving prosecution. See
ibid.
In recent decades, the States and the Federal Govern­
ment have toughened drunk-driving laws, and those ef­
forts have corresponded to a dramatic decrease in alcohol-
related fatalities. As of the early 1980’s, the number of
annual fatalities averaged 25,000; by 2014, the most re­
cent year for which statistics are available, the number
had fallen to below 10,000. Presidential Commission on
Drunk Driving 1 (Nov. 1983); NHTSA, Traffic Safety
Facts, 2014 Data, Alcohol-Impaired Driving 2 (No. 812231,
Dec. 2015) (NHTSA, 2014 Alcohol-Impaired Driving). One

——————
1 In
addition, BAC may be determined by testing a subject’s urine,
which also requires the test subject’s cooperation. But urine tests
appear to be less common in drunk-driving cases than breath and blood
tests, and none of the cases before us involves one.
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Opinion of the Court

legal change has been further lowering the BAC standard
from 0.10% to 0.08%. See 1 Erwin, §2.01[1], at 2–3 to 2–4.
In addition, many States now impose increased penalties
for recidivists and for drivers with a BAC level that ex­
ceeds a higher threshold. In North Dakota, for example,
the standard penalty for first-time drunk-driving offenders
is license suspension and a fine. N. D. Cent. Code Ann.
§39–08–01(5)(a)(1) (Supp. 2015); §39–20–04.1(1). But an
offender with a BAC of 0.16% or higher must spend at
least two days in jail. §39–08–01(5)(a)(2). In addition, the
State imposes increased mandatory minimum sentences
for drunk-driving recidivists. §§39–08–01(5)(b)–(d).
Many other States have taken a similar approach, but
this new structure threatened to undermine the effective­
ness of implied consent laws. If the penalty for driving
with a greatly elevated BAC or for repeat violations ex­
ceeds the penalty for refusing to submit to testing, motor­
ists who fear conviction for the more severely punished
offenses have an incentive to reject testing. And in some
States, the refusal rate is high. On average, over one-fifth
of all drivers asked to submit to BAC testing in 2011
refused to do so. NHTSA, E. Namuswe, H. Coleman, & A.
Berning, Breath Test Refusal Rates in the United States—
2011 Update 1 (No. 811881, Mar. 2014). In North Dakota,
the refusal rate for 2011 was a representative 21%. Id.,
at 2. Minnesota’s was below average, at 12%. Ibid.
To combat the problem of test refusal, some States have
begun to enact laws making it a crime to refuse to undergo
testing. Minnesota has taken this approach for decades.
See 1989 Minn. Laws p. 1658; 1992 Minn. Laws p. 1947.
And that may partly explain why its refusal rate now is
below the national average. Minnesota’s rate is also half
the 24% rate reported for 1988, the year before its first
criminal refusal law took effect. See Ross, Simon, Cleary,
Lewis, & Storkamp, Causes and Consequences of Implied
Consent Refusal, 11 Alcohol, Drugs and Driving 57, 69
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(1995). North Dakota adopted a similar law, in 2013, after
a pair of drunk-driving accidents claimed the lives of an
entire young family and another family’s 5- and 9-year-old
boys.2 2013 N. D. Laws pp. 1087–1088 (codified at §§39–
08–01(1)–(3)). The Federal Government also encourages
this approach as a means for overcoming the incentive
that drunk drivers have to refuse a test. NHTSA, Refusal
of Intoxication Testing, at 20.
II

A

Petitioner Danny Birchfield accidentally drove his car
off a North Dakota highway on October 10, 2013. A state
trooper arrived and watched as Birchfield unsuccessfully
tried to drive back out of the ditch in which his car was
stuck. The trooper approached, caught a strong whiff of
alcohol, and saw that Birchfield’s eyes were bloodshot and
watery. Birchfield spoke in slurred speech and struggled
to stay steady on his feet. At the trooper’s request, Birch-
field agreed to take several field sobriety tests and per­
formed poorly on each. He had trouble reciting sections of
the alphabet and counting backwards in compliance with
the trooper’s directions.
Believing that Birchfield was intoxicated, the trooper
informed him of his obligation under state law to agree to
a BAC test. Birchfield consented to a roadside breath test.
The device used for this sort of test often differs from the
machines used for breath tests administered in a police
station and is intended to provide a preliminary assess­
ment of the driver’s BAC. See, e.g., Berger 1403. Because
the reliability of these preliminary or screening breath
——————
2 See Smith, Moving From Grief to Action: Two Families Push for

Stronger DUI Laws in N. D., Bismarck Tribune, Feb. 2, 2013, p. 1A;
Haga, Some Kind of Peace: Parents of Two Young Boys Killed in
Campground Accident Urge for Tougher DUI Penalties in N. D., Grand
Forks Herald, Jan. 15, 2013, pp. A1–A2.
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Opinion of the Court

tests varies, many jurisdictions do not permit their numer­
ical results to be admitted in a drunk-driving trial as
evidence of a driver’s BAC. See generally 3 Erwin
§24.03[1]. In North Dakota, results from this type of test
are “used only for determining whether or not a further
test shall be given.” N. D. Cent. Code Ann. §39–20–14(3).
In Birchfield’s case, the screening test estimated that his
BAC was 0.254%, more than three times the legal limit of
0.08%. See §39–08–01(1)(a).
The state trooper arrested Birchfield for driving while
impaired, gave the usual Miranda warnings, again ad­
vised him of his obligation under North Dakota law to
undergo BAC testing, and informed him, as state law
requires, see §39–20–01(3)(a), that refusing to take the
test would expose him to criminal penalties. In addition to
mandatory addiction treatment, sentences range from a
mandatory fine of $500 (for first-time offenders) to fines of
at least $2,000 and imprisonment of at least one year and
one day (for serial offenders). §39–08–01(5). These crimi­
nal penalties apply to blood, breath, and urine test refus­
als alike. See §§39–08–01(2), 39–20–01, 39–20–14.
Although faced with the prospect of prosecution under
this law, Birchfield refused to let his blood be drawn. Just
three months before, Birchfield had received a citation for
driving under the influence, and he ultimately pleaded
guilty to that offense. State v. Birchfield, Crim. No. 30–
2013–CR–00720 (Dist. Ct. Morton Cty., N. D., Jan. 27,
2014). This time he also pleaded guilty—to a misde-
meanor violation of the refusal statute—but his plea was
a conditional one: while Birchfield admitted refusing the
blood test, he argued that the Fourth Amendment prohib­
ited criminalizing his refusal to submit to the test. The
State District Court rejected this argument and imposed a
sentence that accounted for his prior conviction. Cf. §39–
08–01(5)(b). The sentence included 30 days in jail (20 of
which were suspended and 10 of which had already been
10 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

served), 1 year of unsupervised probation, $1,750 in fine
and fees, and mandatory participation in a sobriety pro­
gram and in a substance abuse evaluation. App. to Pet.
for Cert. in No. 14–1468, p. 20a.
On appeal, the North Dakota Supreme Court affirmed.
2015 ND 6, 858 N. W. 2d 302. The court found support for
the test refusal statute in this Court’s McNeely plurality
opinion, which had spoken favorably about “acceptable
‘legal tools’ with ‘significant consequences’ for refusing to
submit to testing.” 858 N. W. 2d, at 307 (quoting McNeely,
569 U. S., at ___ (slip op., at 18)).
B
On August 5, 2012, Minnesota police received a report of
a problem at a South St. Paul boat launch. Three appar­
ently intoxicated men had gotten their truck stuck in the
river while attempting to pull their boat out of the water.
When police arrived, witnesses informed them that a man
in underwear had been driving the truck. That man
proved to be William Robert Bernard, Jr., petitioner in the
second of these cases. Bernard admitted that he had been
drinking but denied driving the truck (though he was
holding its keys) and refused to perform any field sobriety
tests. After noting that Bernard’s breath smelled of alco­
hol and that his eyes were bloodshot and watery, officers
arrested Bernard for driving while impaired.
Back at the police station, officers read Bernard Minne­
sota’s implied consent advisory, which like North Dakota’s
informs motorists that it is a crime under state law to
refuse to submit to a legally required BAC test. See Minn.
Stat. §169A.51, subd. 2 (2014). Aside from noncriminal
penalties like license revocation, §169A.52, subd. 3, test
refusal in Minnesota can result in criminal penalties
ranging from no more than 90 days’ imprisonment and up
to a $1,000 fine for a misdemeanor violation to seven
years’ imprisonment and a $14,000 fine for repeat offend­
 Cite as: 579 U. S. ____ (2016) 11

Opinion of the Court

ers, §169A.03, subd. 12; §169A.20, subds. 2–3; §169A.24,
subd. 2; §169A.27, subd. 2.
The officers asked Bernard to take a breath test. After
he refused, prosecutors charged him with test refusal in
the first degree because he had four prior impaired-driving
convictions. 859 N. W. 2d 762, 765, n. 1 (Minn. 2015) (case
below). First-degree refusal carries the highest maximum
penalties and a mandatory minimum 3-year prison sen­
tence. §169A.276, subd. 1.
The Minnesota District Court dismissed the charges on
the ground that the warrantless breath test demanded of
Bernard was not permitted under the Fourth Amendment.
App. to Pet. for Cert. in No. 14–1470, pp. 48a, 59a. The
Minnesota Court of Appeals reversed, id., at 46a, and the
State Supreme Court affirmed that judgment. Based on
the longstanding doctrine that authorizes warrantless
searches incident to a lawful arrest, the high court con­
cluded that police did not need a warrant to insist on a
test of Bernard’s breath. 859 N. W. 2d, at 766–772. Two
justices dissented. Id., at 774–780 (opinion of Page and
Stras, JJ.).
C
A police officer spotted our third petitioner, Steve Mi­
chael Beylund, driving the streets of Bowman, North
Dakota, on the night of August 10, 2013. The officer saw
Beylund try unsuccessfully to turn into a driveway. In the
process, Beylund’s car nearly hit a stop sign before coming
to a stop still partly on the public road. The officer walked
up to the car and saw that Beylund had an empty wine
glass in the center console next to him. Noticing that
Beylund also smelled of alcohol, the officer asked him to
step out of the car. As Beylund did so, he struggled to
keep his balance.
The officer arrested Beylund for driving while impaired
and took him to a nearby hospital. There he read Beylund
12 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

North Dakota’s implied consent advisory, informing him
that test refusal in these circumstances is itself a crime.
See N. D. Cent. Code Ann. §39–20–01(3)(a). Unlike the
other two petitioners in these cases, Beylund agreed to
have his blood drawn and analyzed. A nurse took a blood
sample, which revealed a blood alcohol concentration of
0.250%, more than three times the legal limit.
Given the test results, Beylund’s driver’s license was
suspended for two years after an administrative hearing.
Beylund appealed the hearing officer’s decision to a North
Dakota District Court, principally arguing that his con­
sent to the blood test was coerced by the officer’s warning
that refusing to consent would itself be a crime. The
District Court rejected this argument, and Beylund again
appealed.
The North Dakota Supreme Court affirmed. In re­
sponse to Beylund’s argument that his consent was insuf­
ficiently voluntary because of the announced criminal
penalties for refusal, the court relied on the fact that its
then-recent Birchfield decision had upheld the constitu­
tionality of those penalties. 2015 ND 18, ¶¶14–15, 859
N. W. 2d 403, 408–409. The court also explained that it
had found consent offered by a similarly situated motorist
to be voluntary, State v. Smith, 2014 ND 152, 849 N. W.
2d 599. In that case, the court emphasized that North
Dakota’s implied consent advisory was not misleading
because it truthfully related the penalties for refusal. Id.,
at 606.
We granted certiorari in all three cases and consolidated
them for argument, see 577 U. S. ___ (2015), in order to
decide whether motorists lawfully arrested for drunk
driving may be convicted of a crime or otherwise penalized
for refusing to take a warrantless test measuring the
alcohol in their bloodstream.
 Cite as: 579 U. S. ____ (2016) 13

Opinion of the Court

III
As our summary of the facts and proceedings in these
three cases reveals, the cases differ in some respects.
Petitioners Birchfield and Beylund were told that they
were obligated to submit to a blood test, whereas petitioner
Bernard was informed that a breath test was required.
Birchfield and Bernard each refused to undergo a test and
was convicted of a crime for his refusal. Beylund complied
with the demand for a blood sample, and his license was
then suspended in an administrative proceeding based on
test results that revealed a very high blood alcohol level.
Despite these differences, success for all three petition­
ers depends on the proposition that the criminal law ordi­
narily may not compel a motorist to submit to the taking
of a blood sample or to a breath test unless a warrant
authorizing such testing is issued by a magistrate. If, on
the other hand, such warrantless searches comport with
the Fourth Amendment, it follows that a State may crimi­
nalize the refusal to comply with a demand to submit to
the required testing, just as a State may make it a crime
for a person to obstruct the execution of a valid search
warrant. See, e.g., Conn. Gen. Stat. §54–33d (2009); Fla.
Stat. §933.15 (2015); N. J. Stat. Ann. §33:1–63 (West
1994); 18 U. S. C. §1501; cf. Bumper v. North Carolina,
391 U. S. 543, 550 (1968) (“When a law enforcement officer
claims authority to search a home under a warrant, he
announces in effect that the occupant has no right to resist
the search”). And by the same token, if such warrantless
searches are constitutional, there is no obstacle under
federal law to the admission of the results that they yield
in either a criminal prosecution or a civil or administrative
proceeding. We therefore begin by considering whether
the searches demanded in these cases were consistent
with the Fourth Amendment.
14 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

IV
The Fourth Amendment provides:
“The right of the people to be secure in their per­
sons, houses, papers, and effects, against unreasona­
ble searches and seizures, shall not be violated, and
no Warrants shall issue, but upon probable cause,
supported by Oath or affirmation, and particularly
describing the place to be searched, and the persons or
things to be seized.”
The Amendment thus prohibits “unreasonable searches,”
and our cases establish that the taking of a blood sam-
ple or the administration of a breath test is a search.
See Skinner v. Railway Labor Executives’ Assn., 489 U. S.
602, 616–617 (1989); Schmerber v. California, 384 U. S.
757, 767–768 (1966). The question, then, is whether the
warrantless searches at issue here were reasonable. See
Vernonia School Dist. 47J v. Acton, 515 U. S. 646, 652
(1995) (“As the text of the Fourth Amendment indicates,
the ultimate measure of the constitutionality of a govern­
mental search is ‘reasonableness’ ”).
“[T]he text of the Fourth Amendment does not specify
when a search warrant must be obtained.” Kentucky v.
King, 563 U. S. 452, 459 (2011); see also California v.
Acevedo, 500 U. S. 565, 581 (1991) (Scalia, J., concur-
ring in judgment) (“What [the text] explicitly states regard-
ing warrants is by way of limitation upon their issuance
rather than requirement of their use”). But “this Court has
inferred that a warrant must [usually] be secured.” King,
563 U. S., at 459. This usual requirement, however, is
subject to a number of exceptions. Ibid.
We have previously had occasion to examine whether
one such exception—for “exigent circumstances”—applies
in drunk-driving investigations. The exigent circum-
stances exception allows a warrantless search when an
emergency leaves police insufficient time to seek a warrant.
 Cite as: 579 U. S. ____ (2016) 15

Opinion of the Court

Michigan v. Tyler, 436 U. S. 499, 509 (1978). It permits,
for instance, the warrantless entry of private property
when there is a need to provide urgent aid to those inside,
when police are in hot pursuit of a fleeing suspect, and
when police fear the imminent destruction of evidence.
King, supra, at 460.
In Schmerber v. California, we held that drunk driving
may present such an exigency. There, an officer directed
hospital personnel to take a blood sample from a driver
who was receiving treatment for car crash injuries. 384
U. S., at 758. The Court concluded that the officer “might
reasonably have believed that he was confronted with an
emergency” that left no time to seek a warrant because
“the percentage of alcohol in the blood begins to diminish
shortly after drinking stops.” Id., at 770. On the specific
facts of that case, where time had already been lost taking
the driver to the hospital and investigating the accident,
the Court found no Fourth Amendment violation even
though the warrantless blood draw took place over the
driver’s objection. Id., at 770–772.
More recently, though, we have held that the natural
dissipation of alcohol from the bloodstream does not al-
ways constitute an exigency justifying the warrantless
taking of a blood sample. That was the holding of Mis-
souri v. McNeely, 569 U. S. ___, where the State of Mis­
souri was seeking a per se rule that “whenever an officer
has probable cause to believe an individual has been
driving under the influence of alcohol, exigent circum­
stances will necessarily exist because BAC evidence is
inherently evanescent.” Id., at ___ (opinion of the Court)
(slip op., at 8). We disagreed, emphasizing that Schmerber
had adopted a case-specific analysis depending on “all of
the facts and circumstances of the particular case.” 569
U. S., at ___ (slip op., at 8). We refused to “depart from
careful case-by-case assessment of exigency and adopt the
categorical rule proposed by the State.” Id., at ___ (slip
16 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

op., at 9).
While emphasizing that the exigent-circumstances
exception must be applied on a case-by-case basis, the
McNeely Court noted that other exceptions to the warrant
requirement “apply categorically” rather than in a “case-
specific” fashion. Id., at ___, n. 3 (slip op., at 7, n. 3). One
of these, as the McNeely opinion recognized, is the long-
established rule that a warrantless search may be con­
ducted incident to a lawful arrest. See ibid. But the
Court pointedly did not address any potential justification
for warrantless testing of drunk-driving suspects except
for the exception “at issue in th[e] case,” namely, the
exception for exigent circumstances. Id., at ___ (slip op.,
at 5). Neither did any of the Justices who wrote separately.
See id., at ___–___ (KENNEDY, J., concurring in part)
(slip op., at 1–2); id., at ___–___ (ROBERTS, C. J., concur­
ring in part and dissenting in part) (slip op., at 1–11); id.,
at ___–___ (THOMAS, J., dissenting) (slip op., at 1–8).
In the three cases now before us, the drivers were
searched or told that they were required to submit to a
search after being placed under arrest for drunk driving.
We therefore consider how the search-incident-to-arrest
doctrine applies to breath and blood tests incident to such
arrests.
V

A

The search-incident-to-arrest doctrine has an ancient
pedigree. Well before the Nation’s founding, it was recog­
nized that officers carrying out a lawful arrest had the
authority to make a warrantless search of the arrestee’s
person. An 18th-century manual for justices of the peace
provides a representative picture of usual practice shortly
before the Fourth Amendment’s adoption:
“[A] thorough search of the felon is of the utmost con­
sequence to your own safety, and the benefit of the
 Cite as: 579 U. S. ____ (2016) 17

Opinion of the Court

public, as by this means he will be deprived of in­
struments of mischief, and evidence may probably be
found on him sufficient to convict him, of which, if he
has either time or opportunity allowed him, he will
besure [sic] to find some means to get rid of.” The
Conductor Generalis 117 (J. Parker ed. 1788) (reprint­
ing S. Welch, Observations on the Office of Constable
19 (1754)).
One Fourth Amendment historian has observed that,
prior to American independence, “[a]nyone arrested could
expect that not only his surface clothing but his body,
luggage, and saddlebags would be searched and, perhaps,
his shoes, socks, and mouth as well.” W. Cuddihy, The
Fourth Amendment: Origins and Original Meaning: 602–
1791, p. 420 (2009).
No historical evidence suggests that the Fourth
Amendment altered the permissible bounds of arrestee
searches. On the contrary, legal scholars agree that “the
legitimacy of body searches as an adjunct to the arrest
process had been thoroughly established in colonial times,
so much so that their constitutionality in 1789 can not be
doubted.” Id., at 752; see also T. Taylor, Two Studies in
Constitutional Interpretation 28–29, 39, 45 (1969); Stuntz,
The Substantive Origins of Criminal Procedure, 105 Yale
L. J. 393, 401 (1995).
Few reported cases addressed the legality of such
searches before the 19th century, apparently because the
point was not much contested. In the 19th century, the
subject came up for discussion more often, but court deci­
sions and treatises alike confirmed the searches’ broad
acceptance. E.g., Holker v. Hennessey, 141 Mo. 527, 539–
540, 42 S. W. 1090, 1093 (1897); Ex parte Hurn, 92 Ala.
102, 112, 9 So. 515, 519 (1891); Thatcher v. Weeks, 79 Me.
547, 548–549, 11 A. 599 (1887); Reifsnyder v. Lee, 44 Iowa
101, 103 (1876); F. Wharton, Criminal Pleading and Prac­
18 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

tice §60, p. 45 (8th ed. 1880); 1 J. Bishop, Criminal Proce­
dure §211, p. 127 (2d ed. 1872).
When this Court first addressed the question, we too
confirmed (albeit in dicta) “the right on the part of the
Government, always recognized under English and Ameri­
can law, to search the person of the accused when legally
arrested to discover and seize the fruits or evidence of
crime.” Weeks v. United States, 232 U. S. 383, 392 (1914).
The exception quickly became a fixture in our Fourth
Amendment case law. But in the decades that followed,
we grappled repeatedly with the question of the authority
of arresting officers to search the area surrounding the
arrestee, and our decisions reached results that were not
easy to reconcile. See, e.g., United States v. Lefkowitz, 285
U. S. 452, 464 (1932) (forbidding “unrestrained” search of
room where arrest was made); Harris v. United States, 331
U. S. 145, 149, 152 (1947) (permitting complete search of
arrestee’s four-room apartment); United States v. Rab-
inowitz, 339 U. S. 56, 60–65 (1950) (permitting complete
search of arrestee’s office).
We attempted to clarify the law regarding searches
incident to arrest in Chimel v. California, 395 U. S. 752,
754 (1969), a case in which officers had searched the ar­
restee’s entire three-bedroom house. Chimel endorsed a
general rule that arresting officers, in order to prevent the
arrestee from obtaining a weapon or destroying evidence,
could search both “the person arrested” and “the area
‘within his immediate control.’ ” Id., at 763. “[N]o compa­
rable justification,” we said, supported “routinely search­
ing any room other than that in which an arrest occurs—
or, for that matter, for searching through all the desk
drawers or other closed or concealed areas in that room
itself.” Ibid.
Four years later, in United States v. Robinson, 414 U. S.
218 (1973), we elaborated on Chimel’s meaning. We noted
that the search-incident-to-arrest rule actually comprises
 Cite as: 579 U. S. ____ (2016) 19

Opinion of the Court

“two distinct propositions”: “The first is that a search may
be made of the person of the arrestee by virtue of the
lawful arrest. The second is that a search may be made of
the area within the control of the arrestee.” 414 U. S., at
224. After a thorough review of the relevant common law
history, we repudiated “case-by-case adjudication” of the
question whether an arresting officer had the authority to
carry out a search of the arrestee’s person. Id., at 235.
The permissibility of such searches, we held, does not
depend on whether a search of a particular arrestee is
likely to protect officer safety or evidence: “The authority
to search the person incident to a lawful custodial arrest,
while based upon the need to disarm and to discover evi­
dence, does not depend on what a court may later decide
was the probability in a particular arrest situation that
weapons or evidence would in fact be found upon the
person of the suspect.” Ibid. Instead, the mere “fact of the
lawful arrest” justifies “a full search of the person.” Ibid.
In Robinson itself, that meant that police had acted per­
missibly in searching inside a package of cigarettes found
on the man they arrested. Id., at 236.
Our decision two Terms ago in Riley v. California, 573
U. S. ___ (2014), reaffirmed “Robinson’s categorical rule”
and explained how the rule should be applied in situations
that could not have been envisioned when the Fourth
Amendment was adopted. Id., at ___ (slip op., at 9). Riley
concerned a search of data contained in the memory of a
modern cell phone. “Absent more precise guidance from
the founding era,” the Court wrote, “we generally deter­
mine whether to exempt a given type of search from the
warrant requirement ‘by assessing, on the one hand, the
degree to which it intrudes upon an individual’s privacy
and, on the other, the degree to which it is needed for the
promotion of legitimate governmental interests.’ ” Ibid.
Blood and breath tests to measure blood alcohol concen­
tration are not as new as searches of cell phones, but here,
20 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

as in Riley, the founding era does not provide any defini­
tive guidance as to whether they should be allowed inci­
dent to arrest.3 Lacking such guidance, we engage in the
same mode of analysis as in Riley: we examine “the degree
to which [they] intrud[e] upon an individual’s privacy and
. . . the degree to which [they are] needed for the promo­
tion of legitimate governmental interests.’ ” Ibid.
B
We begin by considering the impact of breath and blood
tests on individual privacy interests, and we will discuss
each type of test in turn.
1
Years ago we said that breath tests do not “implicat[e]
significant privacy concerns.” Skinner, 489 U. S., at 626.
That remains so today.
First, the physical intrusion is almost negligible.
Breath tests “do not require piercing the skin” and entail
“a minimum of inconvenience.” Id., at 625. As Minnesota
describes its version of the breath test, the process re­
quires the arrestee to blow continuously for 4 to 15 sec­
onds into a straw-like mouthpiece that is connected by a
tube to the test machine. Brief for Respondent in No. 14–
1470, p. 20. Independent sources describe other breath
test devices in essentially the same terms. See supra, at 5.
The effort is no more demanding than blowing up a party
balloon.
Petitioner Bernard argues, however, that the process is
nevertheless a significant intrusion because the arrestee
must insert the mouthpiece of the machine into his or her
——————
3 At most, there may be evidence that an arrestee’s mouth could be

searched in appropriate circumstances at the time of the founding. See
W. Cuddihy, Fourth Amendment: Origins and Original Meaning: 602–
1791, p. 420 (2009). Still, searching a mouth for weapons or contraband
is not the same as requiring an arrestee to give up breath or blood.
 Cite as: 579 U. S. ____ (2016) 21

Opinion of the Court

mouth. Reply Brief in No. 14–1470, p. 9. But there is
nothing painful or strange about this requirement. The
use of a straw to drink beverages is a common practice
and one to which few object.
Nor, contrary to Bernard, is the test a significant intru­
sion because it “does not capture an ordinary exhalation of
the kind that routinely is exposed to the public” but in­
stead “ ‘requires a sample of “alveolar” (deep lung) air.’ ”
Brief for Petitioner in No. 14–1470, p. 24. Humans have
never been known to assert a possessory interest in or any
emotional attachment to any of the air in their lungs. The
air that humans exhale is not part of their bodies. Exha­
lation is a natural process—indeed, one that is necessary
for life. Humans cannot hold their breath for more than a
few minutes, and all the air that is breathed into a breath
analyzing machine, including deep lung air, sooner or
later would be exhaled even without the test. See gener-
ally J. Hall, Guyton and Hall Textbook of Medical Physiol­
ogy 519–520 (13th ed. 2016).
In prior cases, we have upheld warrantless searches
involving physical intrusions that were at least as signifi­
cant as that entailed in the administration of a breath
test. Just recently we described the process of collecting a
DNA sample by rubbing a swab on the inside of a person’s
cheek as a “negligible” intrusion. Maryland v. King, 569
U. S. ___, ___ (2013) (slip op., at 8). We have also upheld
scraping underneath a suspect’s fingernails to find evi­
dence of a crime, calling that a “very limited intrusion.”
Cupp v. Murphy, 412 U. S. 291, 296 (1973). A breath test
is no more intrusive than either of these procedures.
Second, breath tests are capable of revealing only one
bit of information, the amount of alcohol in the subject’s
breath. In this respect, they contrast sharply with the
sample of cells collected by the swab in Maryland v. King.
Although the DNA obtained under the law at issue in that
case could lawfully be used only for identification pur-
22 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

poses, 569 U. S., at ___ (slip op., at 5), the process put into
the possession of law enforcement authorities a sample from
which a wealth of additional, highly personal information
could potentially be obtained. A breath test, by contrast,
results in a BAC reading on a machine, nothing more. No
sample of anything is left in the possession of the police.
Finally, participation in a breath test is not an experi­
ence that is likely to cause any great enhancement in the
embarrassment that is inherent in any arrest. See Skin-
ner, supra, at 625 (breath test involves “a minimum of . . .
embarrassment”). The act of blowing into a straw is not
inherently embarrassing, nor are evidentiary breath tests
administered in a manner that causes embarrassment.
Again, such tests are normally administered in private at
a police station, in a patrol car, or in a mobile testing
facility, out of public view. See supra, at 5. Moreover,
once placed under arrest, the individual’s expectation of
privacy is necessarily diminished. Maryland v. King,
supra, at ___–___ (slip op., at 24–25).
For all these reasons, we reiterate what we said in
Skinner: A breath test does not “implicat[e] significant
privacy concerns.” 489 U. S., at 626.
2
Blood tests are a different matter. They “require pierc­
ing the skin” and extract a part of the subject’s body.
Skinner, supra, at 625; see also McNeely, 569 U. S., at ___
(opinion of the Court) (slip op., at 4) (blood draws are “a
compelled physical intrusion beneath [the defendant’s]
skin and into his veins”); id., at ___ (opinion of ROBERTS,
C. J.) (slip op., at 9) (blood draws are “significant bodily
intrusions”). And while humans exhale air from their
lungs many times per minute, humans do not continually
shed blood. It is true, of course, that people voluntarily
submit to the taking of blood samples as part of a physical
examination, and the process involves little pain or risk.
 Cite as: 579 U. S. ____ (2016) 23

Opinion of the Court

See id., at ___ (plurality opinion) (slip op., at 16) (citing
Schmerber, 384 U. S., at 771). Nevertheless, for many, the
process is not one they relish. It is significantly more
intrusive than blowing into a tube. Perhaps that is why
many States’ implied consent laws, including Minnesota’s,
specifically prescribe that breath tests be administered in
the usual drunk-driving case instead of blood tests or give
motorists a measure of choice over which test to take. See
1 Erwin §4.06; Minn. Stat. §169A.51, subd. 3.
In addition, a blood test, unlike a breath test, places in
the hands of law enforcement authorities a sample that
can be preserved and from which it is possible to extract
information beyond a simple BAC reading. Even if the
law enforcement agency is precluded from testing the
blood for any purpose other than to measure BAC, the
potential remains and may result in anxiety for the person
tested.
C
Having assessed the impact of breath and blood testing
on privacy interests, we now look to the States’ asserted
need to obtain BAC readings for persons arrested for
drunk driving.
1
The States and the Federal Government have a “para­
mount interest . . . in preserving the safety of . . . public
highways.” Mackey v. Montrym, 443 U. S. 1, 17 (1979).
Although the number of deaths and injuries caused by
motor vehicle accidents has declined over the years, the
statistics are still staggering. See, e.g., NHTSA, Traffic
Safety Facts 1995—Overview 2 (No. 95F7, 1995) (47,087
fatalities, 3,416,000 injuries in 1988); NHTSA, Traffic
Safety Facts, 2014 Data, Summary of Motor Vehicle
Crashes 1 (No. 812263, May 2016) (Table 1) (29,989 fatali­
ties, 1,648,000 injuries in 2014).
24 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

Alcohol consumption is a leading cause of traffic fatali­
ties and injuries. During the past decade, annual fatali­
ties in drunk-driving accidents ranged from 13,582 deaths
in 2005 to 9,865 deaths in 2011. NHTSA, 2014 Alcohol-
Impaired Driving 2. The most recent data report a total of
9,967 such fatalities in 2014—on average, one death every
53 minutes. Id., at 1. Our cases have long recognized the
“carnage” and “slaughter” caused by drunk drivers. Ne-
ville, 459 U. S., at 558; Breithaupt v. Abram, 352 U. S.
432, 439 (1957).
JUSTICE SOTOMAYOR’s partial dissent suggests that
States’ interests in fighting drunk driving are satisfied
once suspected drunk drivers are arrested, since such
arrests take intoxicated drivers off the roads where they
might do harm. See post, at 9 (opinion concurring in part
and dissenting in part). But of course States are not solely
concerned with neutralizing the threat posed by a drunk
driver who has already gotten behind the wheel. They
also have a compelling interest in creating effective “de­
terrent[s] to drunken driving” so such individuals make
responsible decisions and do not become a threat to others
in the first place. Mackey, supra, at 18.
To deter potential drunk drivers and thereby reduce
alcohol-related injuries, the States and the Federal Gov­
ernment have taken the series of steps that we recounted
earlier. See supra, at 2–8. We briefly recapitulate. After
pegging inebriation to a specific level of blood alcohol,
States passed implied consent laws to induce motorists to
submit to BAC testing. While these laws originally pro­
vided that refusal to submit could result in the loss of the
privilege of driving and the use of evidence of refusal in a
drunk-driving prosecution, more recently States and the
Federal Government have concluded that these conse­
quences are insufficient. In particular, license suspension
alone is unlikely to persuade the most dangerous offend­
ers, such as those who drive with a BAC significantly
 Cite as: 579 U. S. ____ (2016) 25

Opinion of the Court

above the current limit of 0.08% and recidivists, to agree
to a test that would lead to severe criminal sanctions.
NHTSA, Implied Consent Refusal Impact, pp. xvii, 83 (No.
807765, Sept. 1991); NHTSA, Use of Warrants for Breath
Test Refusal 1 (No. 810852, Oct. 2007). The laws at issue
in the present cases—which make it a crime to refuse to
submit to a BAC test—are designed to provide an incen­
tive to cooperate in such cases, and we conclude that they
serve a very important function.
2
Petitioners and JUSTICE SOTOMAYOR contend that the
States and the Federal Government could combat drunk
driving in other ways that do not have the same impact on
personal privacy. Their arguments are unconvincing.
The chief argument on this score is that an officer mak­
ing an arrest for drunk driving should not be allowed to
administer a BAC test unless the officer procures a search
warrant or could not do so in time to obtain usable test
results. The governmental interest in warrantless breath
testing, JUSTICE SOTOMAYOR claims, turns on “ ‘whether
the burden of obtaining a warrant is likely to frustrate the
governmental purpose behind the search.’ ” Post, at 3–4
(quoting Camara v. Municipal Court of City and County of
San Francisco, 387 U. S. 523, 533 (1967)).
This argument contravenes our decisions holding that
the legality of a search incident to arrest must be judged
on the basis of categorical rules. In Robinson, for example,
no one claimed that the object of the search, a package of
cigarettes, presented any danger to the arresting officer or
was at risk of being destroyed in the time that it would
have taken to secure a search warrant. The Court never­
theless upheld the constitutionality of a warrantless
search of the package, concluding that a categorical rule
was needed to give police adequate guidance: “A police
officer’s determination as to how and where to search the
26 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

person of a suspect whom he has arrested is necessarily a
quick ad hoc judgment which the Fourth Amendment does
not require to be broken down in each instance into an
analysis of each step in the search.” 414 U. S., at 235; cf.
Riley, 573 U. S., at ___ (slip op., at 22) (“If police are to
have workable rules, the balancing of the competing inter­
ests must in large part be done on a categorical basis—not
in an ad hoc, case-by-case fashion by individual police
officers” (brackets, ellipsis, and internal quotation marks
omitted)).
It is not surprising, then, that the language JUSTICE
SOTOMAYOR quotes to justify her approach comes not from
our search-incident-to-arrest case law, but a case that
addressed routine home searches for possible housing code
violations. See Camara, 387 U. S., at 526. Camara’s
express concern in the passage that the dissent quotes was
“whether the public interest demands creation of a general
exception to the Fourth Amendment’s warrant require­
ment.” Id., at 533 (emphasis added). Camara did not
explain how to apply an existing exception, let alone the
long-established exception for searches incident to a lawful
arrest, whose applicability, as Robinson and Riley make
plain, has never turned on case-specific variables such as
how quickly the officer will be able to obtain a warrant in
the particular circumstances he faces.
In advocating the case-by-case approach, petitioners and
JUSTICE SOTOMAYOR cite language in our McNeely opin­
ion. See Brief for Petitioner in No. 14–1468, p. 14; post, at
12. But McNeely concerned an exception to the warrant
requirement—for exigent circumstances—that always
requires case-by-case determinations. That was the basis
for our decision in that case. 569 U. S., at ___ (slip op.,
at 9). Although JUSTICE SOTOMAYOR contends that the
categorical search-incident-to-arrest doctrine and case-by­
case exigent circumstances doctrine are actually parts of a
single framework, post, at 6–7, and n. 3, in McNeely the
 Cite as: 579 U. S. ____ (2016) 27

Opinion of the Court

Court was careful to note that the decision did not address
any other exceptions to the warrant requirement, 569
U. S., at ___, n. 3 (slip op., at 7, n. 3).
Petitioners and JUSTICE SOTOMAYOR next suggest that
requiring a warrant for BAC testing in every case in which
a motorist is arrested for drunk driving would not impose
any great burden on the police or the courts. But of course
the same argument could be made about searching
through objects found on the arrestee’s possession, which
our cases permit even in the absence of a warrant. What
about the cigarette package in Robinson? What if a motor­
ist arrested for drunk driving has a flask in his pocket?
What if a motorist arrested for driving while under the
influence of marijuana has what appears to be a mari-
juana cigarette on his person? What about an unmarked
bottle of pills?
If a search warrant were required for every search
incident to arrest that does not involve exigent circum­
stances, the courts would be swamped. And even if we
arbitrarily singled out BAC tests incident to arrest for this
special treatment, as it appears the dissent would do, see
post, at 12–14, the impact on the courts would be consid­
erable. The number of arrests every year for driving
under the influence is enormous—more than 1.1 million in
2014. FBI, Uniform Crime Report, Crime in the United
States, 2014, Arrests 2 (Fall 2015). Particularly in sparsely
populated areas, it would be no small task for courts to
field a large new influx of warrant applications that could
come on any day of the year and at any hour. In many
jurisdictions, judicial officers have the authority to issue
warrants only within their own districts, see, e.g., Fed.
Rule Crim. Proc. 41(b); N. D. Rule Crim. Proc. 41(a)
(2016–2017), and in rural areas, some districts may have
only a small number of judicial officers.
North Dakota, for instance, has only 51 state district
28 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

judges spread across eight judicial districts.4 Those judges
are assisted by 31 magistrates, and there are no magis­
trates in 20 of the State’s 53 counties.5 At any given loca­
tion in the State, then, relatively few state officials have
authority to issue search warrants.6 Yet the State, with a
population of roughly 740,000, sees nearly 7,000 drunk-
driving arrests each year. Office of North Dakota Attor­
ney General, Crime in North Dakota, 2014, pp. 5, 47
(2015). With a small number of judicial officers author­
ized to issue warrants in some parts of the State, the
burden of fielding BAC warrant applications 24 hours per
day, 365 days of the year would not be the light burden
that petitioners and JUSTICE SOTOMAYOR suggest.
In light of this burden and our prior search-incident-to­
arrest precedents, petitioners would at a minimum have to
show some special need for warrants for BAC testing. It is
therefore appropriate to consider the benefits that such
applications would provide. Search warrants protect
privacy in two main ways. First, they ensure that a
search is not carried out unless a neutral magistrate
makes an independent determination that there is proba­
ble cause to believe that evidence will be found. See, e.g.,
Riley, 573 U. S., at ___ (slip op., at 5). Second, if the mag­
istrate finds probable cause, the warrant limits the intru­
sion on privacy by specifying the scope of the search—that
is, the area that can be searched and the items that can be
sought. United States v. Chadwick, 433 U. S. 1, 9 (1977),

——————
4 See North Dakota Supreme Court, All District Judges, http://

www.ndcourts.gov/court/districts/judges.htm (all Internet materials as
last visited June 21, 2016).
5 See North Dakota Supreme Court, Magistrates, http://www.ndcourts.gov/

court/counties/magistra/members.htm.
6 North Dakota Supreme Court justices apparently also have author-

ity to issue warrants statewide. See ND Op. Atty. Gen. 99–L–132, p. 2
(Dec. 30, 1999). But we highly doubt that they regularly handle search-
warrant applications, much less during graveyard shifts.
 Cite as: 579 U. S. ____ (2016) 29

Opinion of the Court

abrogated on other grounds, Acevedo, 500 U. S. 565.
How well would these functions be performed by the
warrant applications that petitioners propose? In order to
persuade a magistrate that there is probable cause for a
search warrant, the officer would typically recite the same
facts that led the officer to find that there was probable
cause for arrest, namely, that there is probable cause to
believe that a BAC test will reveal that the motorist’s
blood alcohol level is over the limit. As these three cases
suggest, see Part II, supra, the facts that establish proba­
ble cause are largely the same from one drunk-driving
stop to the next and consist largely of the officer’s own
characterization of his or her observations—for example,
that there was a strong odor of alcohol, that the motorist
wobbled when attempting to stand, that the motorist
paused when reciting the alphabet or counting backwards,
and so on. A magistrate would be in a poor position to
challenge such characterizations.
As for the second function served by search warrants—
delineating the scope of a search—the warrants in ques­
tion here would not serve that function at all. In every
case the scope of the warrant would simply be a BAC test
of the arrestee. Cf. Skinner, 489 U. S., at 622 (“[I]n light
of the standardized nature of the tests and the minimal
discretion vested in those charged with administering the
program, there are virtually no facts for a neutral magis­
trate to evaluate”). For these reasons, requiring the police
to obtain a warrant in every case would impose a substan­
tial burden but no commensurate benefit.
Petitioners advance other alternatives to warrantless
BAC tests incident to arrest, but these are poor substi­
tutes. Relying on a recent NHTSA report, petitioner
Birchfield identifies 19 strategies that he claims would be
at least as effective as implied consent laws, including
high-visibility sobriety checkpoints, installing ignition
interlocks on repeat offenders’ cars that would disable
30 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

their operation when the driver’s breath reveals a suffi­
ciently high alcohol concentration, and alcohol treatment
programs. Brief for Petitioner in No. 14–1468, at 44–45.
But Birchfield ignores the fact that the cited report de­
scribes many of these measures, such as checkpoints, as
significantly more costly than test refusal penalties.
NHTSA, A. Goodwin et al., Countermeasures That Work:
A Highway Safety Countermeasures Guide for State
Highway Safety Offices, p. 1–7 (No. 811727, 7th ed. 2013).
Others, such as ignition interlocks, target only a segment
of the drunk-driver population. And still others, such as
treatment programs, are already in widespread use, see
id., at 1–8, including in North Dakota and Minnesota.
Moreover, the same NHTSA report, in line with the agen­
cy’s guidance elsewhere, stresses that BAC test refusal
penalties would be more effective if the consequences for
refusal were made more severe, including through the
addition of criminal penalties. Id., at 1–16 to 1–17.
3
Petitioner Bernard objects to the whole idea of analyz­
ing breath and blood tests as searches incident to arrest.
That doctrine, he argues, does not protect the sort of gov­
ernmental interests that warrantless breath and blood
tests serve. On his reading, this Court’s precedents per­
mit a search of an arrestee solely to prevent the arrestee
from obtaining a weapon or taking steps to destroy evi­
dence. See Reply Brief in No. 14–1470, at 4–6. In Chimel,
for example, the Court derived its limitation for the scope
of the permitted search—“the area into which an arrestee
might reach”—from the principle that officers may rea­
sonably search “the area from within which he might gain
possession of a weapon or destructible evidence.” 395
U. S., at 763. Stopping an arrestee from destroying evi­
dence, Bernard argues, is critically different from prevent­
ing the loss of blood alcohol evidence as the result of the
 Cite as: 579 U. S. ____ (2016) 31

Opinion of the Court

body’s metabolism of alcohol, a natural process over which
the arrestee has little control. Reply Brief in No. 14–1470,
at 5–6.
The distinction that Bernard draws between an ar­
restee’s active destruction of evidence and the loss of
evidence due to a natural process makes little sense. In
both situations the State is justifiably concerned that
evidence may be lost, and Bernard does not explain why
the cause of the loss should be dispositive. And in fact
many of this Court’s post-Chimel cases have recognized
the State’s concern, not just in avoiding an arrestee’s
intentional destruction of evidence, but in “evidence
preservation” or avoiding “the loss of evidence” more gen­
erally. Riley, 573 U. S., at ___ (slip op., at 8); see also
Robinson, 414 U. S., at 234 (“the need to preserve evidence
on his person”); Knowles v. Iowa, 525 U. S. 113, 118–119
(1998) (“the need to discover and preserve evidence;” “the
concern for destruction or loss of evidence” (emphasis
added)); Virginia v. Moore, 553 U. S. 164, 176 (2008) (the
need to “safeguard evidence”). This concern for preserving
evidence or preventing its loss readily encompasses the
inevitable metabolization of alcohol in the blood.
Nor is there any reason to suspect that Chimel’s use of
the word “destruction,” 395 U. S., at 763, was a deliberate
decision to rule out evidence loss that is mostly beyond the
arrestee’s control. The case did not involve any evidence
that was subject to dissipation through natural processes,
and there is no sign in the opinion that such a situation
was on the Court’s mind.
Bernard attempts to derive more concrete support for
his position from Schmerber. In that case, the Court
stated that the “destruction of evidence under the direct
control of the accused” is a danger that is not present
“with respect to searches involving intrusions beyond the
body’s surface.” 384 U. S., at 769. Bernard reads this to
mean that an arrestee cannot be required “to take a chem­
32 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

ical test” incident to arrest, Brief for Petitioner in No. 14–
1470, at 19, but by using the term “chemical test,” Ber­
nard obscures the fact that Schmerber’s passage was
addressed to the type of test at issue in that case, namely
a blood test. The Court described blood tests as “searches
involving intrusions beyond the body’s surface,” and it saw
these searches as implicating important “interests in
human dignity and privacy,” 384 U. S., at 769–770. Al-
though the Court appreciated as well that blood tests “in­
volv[e] virtually no risk, trauma, or pain,” id., at 771, its
point was that such searches still impinge on far more
sensitive interests than the typical search of the person of
an arrestee. Cf. supra, at 22–23. But breath tests, unlike
blood tests, “are not invasive of the body,” Skinner, 489
U. S., at 626 (emphasis added), and therefore the Court’s
comments in Schmerber are inapposite when it comes to
the type of test Bernard was asked to take. Schmerber did
not involve a breath test, and on the question of breath
tests’ legality, Schmerber said nothing.
Finally, Bernard supports his distinction using a pas­
sage from the McNeely opinion, which distinguishes be­
tween “easily disposable evidence” over “which the suspect
has control” and evidence, like blood alcohol evidence, that
is lost through a natural process “in a gradual and rela­
tively predictable manner.” 569 U. S., at ___ (slip op., at
10); see Reply Brief in No. 14–1470, at 5–6. Bernard fails
to note the issue that this paragraph addressed. McNeely
concerned only one exception to the usual warrant re­
quirement, the exception for exigent circumstances, and as
previously discussed, that exception has always been
understood to involve an evaluation of the particular facts
of each case. Here, by contrast, we are concerned with the
search-incident-to-arrest exception, and as we made clear
in Robinson and repeated in McNeely itself, this authority
is categorical. It does not depend on an evaluation of the
threat to officer safety or the threat of evidence loss in a
 Cite as: 579 U. S. ____ (2016) 33

Opinion of the Court

particular case.7
Having assessed the effect of BAC tests on privacy
interests and the need for such tests, we conclude that the
Fourth Amendment permits warrantless breath tests
incident to arrests for drunk driving. The impact of
breath tests on privacy is slight, and the need for BAC
testing is great.
We reach a different conclusion with respect to blood
tests. Blood tests are significantly more intrusive, and
their reasonableness must be judged in light of the availa­
bility of the less invasive alternative of a breath test.
Respondents have offered no satisfactory justification for
demanding the more intrusive alternative without a
warrant.
Neither respondents nor their amici dispute the effec­
——————
7 JUSTICE SOTOMAYOR objects to treating warrantless breath tests as

searches incident to a lawful arrest on two additional grounds.
First, she maintains that “[a]ll of this Court’s postarrest exceptions to
the warrant requirement require a law enforcement interest separate
from criminal investigation.” Post, at 14. At least with respect to the
search-incident-to-arrest doctrine, that is not true. As the historical
authorities discussed earlier attest, see Part V–A, supra, the doctrine
has always been understood as serving investigative ends, such as
“discover[ing] and seiz[ing] . . . evidences of crime.” Weeks v. United
States, 232 U. S. 383, 392 (1914); see also United States v. Robinson,
414 U. S. 218, 235 (1973) (emphasizing “the need . . . to discover evi­
dence”). Using breath tests to obtain evidence of intoxication is there­
fore well within the historical understanding of the doctrine’s purposes.
Second, JUSTICE SOTOMAYOR contends that the search-incident-to­
arrest doctrine does not apply when “a narrower exception to the
warrant requirement adequately satisfies the governmental needs
asserted.” Post, at 7, n. 3; see also post, at 17–19. But while this
Court’s cases have certainly recognized that “more targeted” exceptions
to the warrant requirement may justify a warrantless search even
when the search-incident-to-arrest exception would not, Riley v. Cali-
fornia, 573 U. S. ___, ___ (2014) (slip op., at 14), JUSTICE SOTOMAYOR
cites no authority for the proposition that an exception to the warrant
requirement cannot apply simply because a “narrower” exception might
apply.
34 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

tiveness of breath tests in measuring BAC. Breath tests
have been in common use for many years. Their results
are admissible in court and are widely credited by juries,
and respondents do not dispute their accuracy or utility.
What, then, is the justification for warrantless blood tests?
One advantage of blood tests is their ability to detect not
just alcohol but also other substances that can impair a
driver’s ability to operate a car safely. See Brief for New
Jersey et al. as Amici Curiae 9; Brief for United States as
Amicus Curiae 6. A breath test cannot do this, but police
have other measures at their disposal when they have
reason to believe that a motorist may be under the influ­
ence of some other substance (for example, if a breath test
indicates that a clearly impaired motorist has little if any
alcohol in his blood). Nothing prevents the police from
seeking a warrant for a blood test when there is sufficient
time to do so in the particular circumstances or from
relying on the exigent circumstances exception to the
warrant requirement when there is not. See McNeely, 569
U. S., at ___–___ (slip op., at 22–23).
A blood test also requires less driver participation than
a breath test. In order for a technician to take a blood
sample, all that is needed is for the subject to remain still,
either voluntarily or by being immobilized. Thus, it is
possible to extract a blood sample from a subject who
forcibly resists, but many States reasonably prefer not to
take this step. See, e.g., Neville, 459 U. S., at 559–560.
North Dakota, for example, tells us that it generally op­
poses this practice because of the risk of dangerous alter­
cations between police officers and arrestees in rural areas
where the arresting officer may not have backup. Brief for
Respondent in No. 14–1468, p. 29. Under current North
Dakota law, only in cases involving an accident that re­
sults in death or serious injury may blood be taken from
arrestees who resist. Compare N. D. Cent. Code Ann.
§§39–20–04(1), 39–20–01, with §39–20–01.1.
 Cite as: 579 U. S. ____ (2016) 35

Opinion of the Court

It is true that a blood test, unlike a breath test, may be
administered to a person who is unconscious (perhaps as a
result of a crash) or who is unable to do what is needed to
take a breath test due to profound intoxication or injuries.
But we have no reason to believe that such situations are
common in drunk-driving arrests, and when they arise,
the police may apply for a warrant if need be.
A breath test may also be ineffective if an arrestee
deliberately attempts to prevent an accurate reading by
failing to blow into the tube for the requisite length of time
or with the necessary force. But courts have held that
such conduct qualifies as a refusal to undergo testing, e.g.,
Andrews v. Turner, 52 Ohio St. 2d 31, 36–37, 368 N. E. 2d
1253, 1256–1257 (1977); In re Kunneman, 501 P. 2d 910,
910–911 (Okla. Civ. App. 1972); see generally 1 Erwin
§4.08[2] (collecting cases), and it may be prosecuted as
such. And again, a warrant for a blood test may be
sought.
Because breath tests are significantly less intrusive
than blood tests and in most cases amply serve law en­
forcement interests, we conclude that a breath test, but
not a blood test, may be administered as a search incident
to a lawful arrest for drunk driving. As in all cases involv­
ing reasonable searches incident to arrest, a warrant is
not needed in this situation.8
——————
8 JUSTICE THOMAS partly dissents from this holding, calling any dis­

tinction between breath and blood tests “an arbitrary line in the sand.”
Post, at 3 (opinion concurring in judgment in part and dissenting in
part). Adhering to a position that the Court rejected in McNeely,
JUSTICE THOMAS would hold that both breath and blood tests are
constitutional with or without a warrant because of the natural metab­
olization of alcohol in the bloodstream. Post, at 3–5. Yet JUSTICE
THOMAS does not dispute our conclusions that blood draws are more
invasive than breath tests, that breath tests generally serve state
interests in combating drunk driving as effectively as blood tests, and
that our decision in Riley calls for a balancing of individual privacy
interests and legitimate state interests to determine the reasonableness
36 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

VI
Having concluded that the search incident to arrest
doctrine does not justify the warrantless taking of a blood
sample, we must address respondents’ alternative argu­
ment that such tests are justified based on the driver’s
legally implied consent to submit to them. It is well estab­
lished that a search is reasonable when the subject con­
sents, e.g., Schneckloth v. Bustamonte, 412 U. S. 218, 219
(1973), and that sometimes consent to a search need not
be express but may be fairly inferred from context, cf.
Florida v. Jardines, 569 U. S. 1, ___–___ (2013) (slip op., at
6–7); Marshall v. Barlow’s, Inc., 436 U. S. 307, 313 (1978).
Our prior opinions have referred approvingly to the gen­
eral concept of implied-consent laws that impose civil
penalties and evidentiary consequences on motorists who
refuse to comply. See, e.g., McNeely, supra, at ___ (plural-
ity opinion) (slip op., at 18); Neville, supra, at 560. Peti­
tioners do not question the constitutionality of those laws,
and nothing we say here should be read to cast doubt on
them.
It is another matter, however, for a State not only to
insist upon an intrusive blood test, but also to impose
criminal penalties on the refusal to submit to such a test.
There must be a limit to the consequences to which motor­
ists may be deemed to have consented by virtue of a deci­
sion to drive on public roads.
Respondents and their amici all but concede this point.
North Dakota emphasizes that its law makes refusal a
misdemeanor and suggests that laws punishing refusal
——————
of the category of warrantless search that is at issue. Contrary to
JUSTICE THOMAS’s contention, this balancing does not leave law en­
forcement officers or lower courts with unpredictable rules, because it is
categorical and not “case-by-case,” post, at 3. Indeed, today’s decision
provides very clear guidance that the Fourth Amendment allows
warrantless breath tests, but as a general rule does not allow warrant-
less blood draws, incident to a lawful drunk-driving arrest.
 Cite as: 579 U. S. ____ (2016) 37

Opinion of the Court

more severely would present a different issue. Brief for
Respondent in No. 14–1468, at 33–34. Borrowing from our
Fifth Amendment jurisprudence, the United States sug­
gests that motorists could be deemed to have consented to
only those conditions that are “reasonable” in that they
have a “nexus” to the privilege of driving and entail penal­
ties that are proportional to severity of the violation.
Brief for United States as Amicus Curiae 21–27. But in
the Fourth Amendment setting, this standard does not
differ in substance from the one that we apply, since rea­
sonableness is always the touchstone of Fourth Amend­
ment analysis, see Brigham City v. Stuart, 547 U. S. 398,
403 (2006). And applying this standard, we conclude that
motorists cannot be deemed to have consented to submit
to a blood test on pain of committing a criminal offense.
VII
Our remaining task is to apply our legal conclusions to
the three cases before us.
Petitioner Birchfield was criminally prosecuted for
refusing a warrantless blood draw, and therefore the
search he refused cannot be justified as a search incident
to his arrest or on the basis of implied consent. There is
no indication in the record or briefing that a breath test
would have failed to satisfy the State’s interests in acquir­
ing evidence to enforce its drunk-driving laws against
Birchfield. And North Dakota has not presented any case-
specific information to suggest that the exigent circum­
stances exception would have justified a warrantless
search. Cf. McNeely, 569 U. S., at ___–___ (slip op., at 20–
23). Unable to see any other basis on which to justify a
warrantless test of Birchfield’s blood, we conclude that
Birchfield was threatened with an unlawful search and
that the judgment affirming his conviction must be
reversed.
Bernard, on the other hand, was criminally prosecuted
38 BIRCHFIELD v. NORTH DAKOTA

Opinion of the Court

for refusing a warrantless breath test. That test was a
permissible search incident to Bernard’s arrest for drunk
driving, an arrest whose legality Bernard has not con-
tested. Accordingly, the Fourth Amendment did not re­
quire officers to obtain a warrant prior to demanding the
test, and Bernard had no right to refuse it.
Unlike the other petitioners, Beylund was not prose-
cuted for refusing a test. He submitted to a blood test after
police told him that the law required his submission, and
his license was then suspended and he was fined in an
administrative proceeding. The North Dakota Supreme
Court held that Beylund’s consent was voluntary on the
erroneous assumption that the State could permissibly
compel both blood and breath tests. Because voluntari­
ness of consent to a search must be “determined from the
totality of all the circumstances,” Schneckloth, supra, at
227, we leave it to the state court on remand to reevaluate
Beylund’s consent given the partial inaccuracy of the
officer’s advisory.9
We accordingly reverse the judgment of the North Da­
kota Supreme Court in No. 14–1468 and remand the case for
further proceedings not inconsistent with this opinion. We
affirm the judgment of the Minnesota Supreme Court in
No. 14–1470. And we vacate the judgment of the North
Dakota Supreme Court in No. 14–1507 and remand the
case for further proceedings not inconsistent with this
opinion.
It is so ordered.
——————
9 If the court on remand finds that Beylund did not voluntarily con­

sent, it will have to address whether the evidence obtained in the
search must be suppressed when the search was carried out pursuant
to a state statute, see Heien v. North Carolina, 574 U. S. ___, ___–___
(2014) (slip op., at 8–10), and the evidence is offered in an administra­
tive rather than criminal proceeding, see Pennsylvania Bd. of Probation
and Parole v. Scott, 524 U. S. 357, 363–364 (1998). And as Beylund
notes, remedies may be available to him under state law. See Brief for
Petitioner in No. 14–1507, pp. 13–14.
 Cite as: 579 U. S. ____ (2016) 1

Opinion of SOTOMAYOR, J.

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 14–1468, 14–1470, and 14–1507
_________________

DANNY BIRCHFIELD, PETITIONER
14–1468 v.
NORTH DAKOTA;
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

NORTH DAKOTA

WILLIAM ROBERT BERNARD, JR., PETITIONER
14–1470 v.
MINNESOTA; AND
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

MINNESOTA

STEVE MICHAEL BEYLUND, PETITIONER
14–1507 v.
GRANT LEVI, DIRECTOR, NORTH DAKOTA
DEPARTMENT OF TRANSPORTATION
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

NORTH DAKOTA

[June 23, 2016]

JUSTICE SOTOMAYOR, with whom JUSTICE GINSBURG
joins, concurring in part and dissenting in part.
The Court today considers three consolidated cases. I
join the majority’s disposition of Birchfield v. North Da-
kota, No. 14–1468, and Beylund v. Levi, No. 14–1507, in
which the Court holds that the search-incident-to-arrest
exception to the Fourth Amendment’s warrant require-
ment does not permit warrantless blood tests. But I dis-
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Opinion of SOTOMAYOR, J.

sent from the Court’s disposition of Bernard v. Minnesota,
No. 14–1470, in which the Court holds that the same
exception permits warrantless breath tests. Because no
governmental interest categorically makes it impractical
for an officer to obtain a warrant before measuring a
driver’s alcohol level, the Fourth Amendment prohibits
such searches without a warrant, unless exigent circum-
stances exist in a particular case.1
I

A

As the Court recognizes, the proper disposition of this
case turns on whether the Fourth Amendment guarantees
a right not to be subjected to a warrantless breath test
after being arrested. The Fourth Amendment provides:
“The right of the people to be secure in their persons,
houses, papers, and effects, against unreasonable
searches and seizures, shall not be violated, and no
Warrants shall issue, but upon probable cause, sup-
ported by Oath or affirmation, and particularly de-
scribing the place to be searched, and the persons or
things to be seized.”
The “ultimate touchstone of the Fourth Amendment is
‘reasonableness.’ ” Brigham City v. Stuart, 547 U. S. 398,
403 (2006). A citizen’s Fourth Amendment right to be free
from “unreasonable searches” does not disappear upon
arrest. Police officers may want to conduct a range of
searches after placing a person under arrest. They may
want to pat the arrestee down, search her pockets and
purse, peek inside her wallet, scroll through her cellphone,
examine her car or dwelling, swab her cheeks, or take
——————
1 Because I see no justification for warrantless blood or warrantless
breath tests, I also dissent from the parts of the majority opinion that
justify its conclusions with respect to blood tests on the availability of
warrantless breath tests. See ante, at 33-34.
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Opinion of SOTOMAYOR, J.

blood and breath samples to determine her level of intoxi-
cation. But an officer is not authorized to conduct all of
these searches simply because he has arrested someone.
Each search must be separately analyzed to determine its
reasonableness.
Both before and after a person has been arrested, war-
rants are the usual safeguard against unreasonable
searches because they guarantee that the search is not a
“random or arbitrary ac[t] of government agents,” but is
instead “narrowly limited in its objectives and scope.”
Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602,
622 (1989). Warrants provide the “detached scrutiny of a
neutral magistrate, and thus ensur[e] an objective deter-
mination whether an intrusion is justified.” Ibid. And
they give life to our instruction that the Fourth Amend-
ment “is designed to prevent, not simply to redress, unlaw-
ful police action.” Steagald v. United States, 451 U. S.
204, 215 (1981) (internal quotation marks omitted).
Because securing a warrant before a search is the rule of
reasonableness, the warrant requirement is “subject only
to a few specifically established and well-delineated excep-
tions.” Katz v. United States, 389 U. S. 347, 357 (1967).
To determine whether to “exempt a given type of search
from the warrant requirement,” this Court traditionally
“assess[es], on the one hand, the degree to which it in-
trudes upon an individual’s privacy and, on the other, the
degree to which it is needed for the promotion of legiti-
mate governmental interests.” Riley v. California, 573
U. S. ___, ___ (2014) (slip op., at 9) (internal quotation
marks omitted). In weighing “whether the public interest
demands creation of a general exception to the Fourth
Amendment’s warrant requirement, the question is not
whether the public interest justifies the type of search in
question,” but, more specifically, “whether the burden of
obtaining a warrant is likely to frustrate the governmental
purpose behind the search.” Camara v. Municipal Court
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Opinion of SOTOMAYOR, J.

of City and County of San Francisco, 387 U. S. 523, 533
(1967); see also Almeida-Sanchez v. United States, 413
U. S. 266, 282–283 (1973) (Powell, J., concurring) (noting
that in areas ranging from building inspections to auto-
mobile searches, the Court’s “general approach to excep-
tions to the warrant requirement” is to determine whether
a “ ‘warrant system can be constructed that would be
feasible and meaningful’ ”); United States v. United States
Dist. Court for Eastern Dist. of Mich., 407 U. S. 297, 315
(1972) (“We must . . . ask whether a warrant requirement
would unduly frustrate the [governmental interest]”).2
Applying these principles in past cases, this Court has
recognized two kinds of exceptions to the warrant re-
quirement that are implicated here: (1) case-by-case ex-
ceptions, where the particularities of an individual case
justify a warrantless search in that instance, but not
others; and (2) categorical exceptions, where the common-
alities among a class of cases justify dispensing with the
warrant requirement for all of those cases, regardless of
their individual circumstances.
Relevant here, the Court allows warrantless searches on
a case-by-case basis where the “exigencies” of the particu-
lar case “make the needs of law enforcement so compelling
that a warrantless search is objectively reasonable” in that
——————
2 The Court is wrong to suggest that because the States are seeking

an extension of the “existing” search-incident-to-arrest exception rather
than the “creation” of a new exception for breath searches, this Court
need not determine whether the governmental interest in these searches
can be accomplished without excusing the warrant requirement. Ante,
at 26. To the contrary, as the very sentence the Court cites il-
lustrates, the question is always whether the particular “type of
search in question” is reasonable if conducted without a warrant.
Camara, 387 U. S., at 533. To answer that question, in every case,
courts must ask whether the “burden of obtaining a warrant is likely to
frustrate the governmental purpose behind the search.” Ibid. This
question may be answered based on existing doctrine, or it may require
the creation of new doctrine, but it must always be asked.
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Opinion of SOTOMAYOR, J.

instance. Missouri v. McNeely, 569 U. S. ___, ___ (2013)
(slip op., at 5) (quoting Kentucky v. King, 563 U. S. 452,
460 (2011)). The defining feature of the exigent circum-
stances exception is that the need for the search becomes
clear only after “all of the facts and circumstances of the
particular case” have been considered in light of the “total-
ity of the circumstances.” 569 U. S., at ___ (slip op., at 8).
Exigencies can include officers’ “need to provide emer-
gency assistance to an occupant of a home, engage in ‘hot
pursuit’ of a fleeing suspect, or enter a burning building to
put out a fire and investigate its cause.” Id., at ___ (slip
op., at 5) (citations omitted).
Exigencies can also arise in efforts to measure a driver’s
blood alcohol level. In Schmerber v. California, 384 U. S.
757 (1966), for instance, a man sustained injuries in a car
accident and was transported to the hospital. While there,
a police officer arrested him for drunk driving and ordered
a warrantless blood test to measure his blood alcohol
content. This Court noted that although the warrant
requirement generally applies to postarrest blood tests, a
warrantless search was justified in that case because
several hours had passed while the police investigated the
scene of the crime and Schmerber was taken to the hospi-
tal, precluding a timely securing of a warrant. Id., at 770–
771.
This Court also recognizes some forms of searches in
which the governmental interest will “categorically” out-
weigh the person’s privacy interest in virtually any cir-
cumstance in which the search is conducted. Relevant
here is the search-incident-to-arrest exception. That
exception allows officers to conduct a limited postarrest
search without a warrant to combat risks that could arise
in any arrest situation before a warrant could be obtained:
“ ‘to remove any weapons that the [arrestee] might seek to
use in order to resist arrest or effect his escape’ ” and to
“ ‘seize any evidence on the arrestee’s person in order to
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Opinion of SOTOMAYOR, J.

prevent its concealment or destruction.’ ” Riley, 573 U. S.,
at ___ (slip op., at 6) (quoting Chimel v. California, 395
U. S. 752, 763 (1969)). That rule applies “categorical[ly]”
to all arrests because the need for the warrantless search
arises from the very “fact of the lawful arrest,” not from
the reason for arrest or the circumstances surrounding it.
United States v. Robinson, 414 U. S. 218, 225, 235 (1973).
Given these different kinds of exceptions to the warrant
requirement, if some form of exception is necessary for a
particular kind of postarrest search, the next step is to ask
whether the governmental need to conduct a warrantless
search arises from “threats” that “ ‘lurk in all custodial
arrests’ ” and therefore “justif[ies] dispensing with the
warrant requirement across the board,” or, instead,
whether the threats “may be implicated in a particular
way in a particular case” and are therefore “better ad-
dressed through consideration of case-specific exceptions
to the warrant requirement, such as the one for exigent
circumstances.” Riley, 573 U. S., at ___ (slip op., at 11–12)
(alterations and internal quotation marks omitted).
To condense these doctrinal considerations into a
straightforward rule, the question is whether, in light of
the individual’s privacy, a “legitimate governmental inter-
est” justifies warrantless searches—and, if so, whether
that governmental interest is adequately addressed by a
case-by-case exception or requires by its nature a categori-
cal exception to the warrant requirement.
B
This Court has twice applied this framework in recent
terms. Riley v. California, 573 U. S. ___,addressed whether,
after placing a person under arrest, a police officer may
conduct a warrantless search of his cell phone data. Cali-
fornia asked for a categorical rule, but the Court rejected
that request, concluding that cell phones do not present
the generic arrest-related harms that have long justified
 Cite as: 579 U. S. ____ (2016) 7

Opinion of SOTOMAYOR, J.

the search-incident-to-arrest exception. The Court found
that phone data posed neither a danger to officer safety
nor a risk of evidence destruction once the physical phone
was secured. Id., at ___–___ (slip op., at 10–15). The
Court nevertheless acknowledged that the exigent circum-
stances exception might be available in a “now or never
situation.” Id., at ___ (slip op., at 15) (internal quotation
marks omitted). It emphasized that “[i]n light of the
availability of the exigent circumstances exception, there
is no reason to believe that law enforcement officers will
not be able to address” the rare needs that would require
an on-the-spot search. Id., at ___ (slip op., at 26).
Similarly, Missouri v. McNeely, 569 U. S. ___,applied
this doctrinal analysis to a case involving police efforts to
measure drivers’ blood alcohol levels. In that case, Mis-
souri argued that the natural dissipation of alcohol in a
person’s blood justified a per se exigent circumstances
exception to the warrant requirement—in essence, a new
kind of categorical exception. The Court recognized that
exigencies could exist, like in Schmerber, that would jus-
tify warrantless searches. 569 U. S., at ___ (slip op., at 9).
But it also noted that in many drunk driving situations,
no such exigencies exist. Where, for instance, “the war-
rant process will not significantly increase the delay” in
testing “because an officer can take steps to secure a war-
rant” while the subject is being prepared for the test, there
is “no plausible justification for an exception to the war-
rant requirement.” Id., at ___ (slip op., at 10). The Court
thus found it unnecessary to “depart from careful case-by-
case assessment of exigency and adopt the categorical rule
proposed by the State.” Id., at ___ (slip op., at 9).3
——————
3 The Court quibbles with our unremarkable statement that the cate-

gorical search-incident-to-arrest doctrine and the case-by-case exigent
circumstances doctrine are part of the same framework by arguing that
a footnote in McNeely was “careful to note that the decision did not
address any other exceptions to the warrant requirement.” Ante, at 26-
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Opinion of SOTOMAYOR, J.

II
The States do not challenge McNeely’s holding that a
categorical exigency exception is not necessary to accom-
modate the governmental interests associated with the
dissipation of blood alcohol after drunk-driving arrests.
They instead seek to exempt breath tests from the war-
rant requirement categorically under the search-incident-
to-arrest doctrine. The majority agrees. Both are wrong.
As discussed above, regardless of the exception a State
requests, the Court’s traditional framework asks whether,
in light of the privacy interest at stake, a legitimate gov-
——————
27 (citing McNeely, 569 U. S., at ___, n. 3 (slip op., at 7, n. 3)). That
footnote explains the difference between categorical exceptions and
case-by-case exceptions generally. Id., at ___, n. 3. It does nothing to
suggest that the two forms of exceptions should not be considered
together when analyzing whether it is reasonable to exempt categori-
cally a particular form of search from the Fourth Amendment’s warrant
requirement.
It should go without saying that any analysis of whether to apply a
Fourth Amendment warrant exception must necessarily be compara-
tive. If a narrower exception to the warrant requirement adequately
satisfies the governmental needs asserted, a more sweeping exception
will be overbroad and could lead to unnecessary and “unreasonable
searches” under the Fourth Amendment. Contrary to the Court’s
suggestion that “no authority” supports this proposition, see ante, at 33
n. 8, our cases have often deployed this commonsense comparative
check. See Riley v. California, 573 U. S. ___, ___–___ (2014) (slip op., at
14–15) (rejecting the application of the search-incident-to-arrest excep-
tion because the exigency exception is a “more targeted wa[y] to ad-
dress [the government’s] concerns”); id., at ___ (slip op., at 11) (analyz-
ing whether the governmental interest can be “better addressed
through consideration of case-specific exceptions to the warrant re-
quirement”); id., at __ (slip op., at 26–27) (noting that “[i]n light of the
availability of the exigent circumstances exception, there is no reason
to believe that” the governmental interest cannot be satisfied without a
categorical search-incident-to-arrest exception); McNeely, 569 U. S., at
___ (slip op., at 9–10) (holding that the availability of the exigency
exception for circumstances that “make obtaining a warrant impracti-
cal” is “reason . . . not to accept the ‘considerable overgeneralization’
that a per se rule would reflect”).
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Opinion of SOTOMAYOR, J.

ernmental interest ever requires conducting breath
searches without a warrant—and, if so, whether that
governmental interest is adequately addressed by a case-
by-case exception or requires a categorical exception to the
warrant requirement. That framework directs the conclu-
sion that a categorical search-incident-to-arrest rule for
breath tests is unnecessary to address the States’ govern-
mental interests in combating drunk driving.
A
Beginning with the governmental interests, there can be
no dispute that States must have tools to combat drunk
driving. See ante, at 2–8. But neither the States nor the
Court has demonstrated that “obtaining a warrant” in
cases not already covered by the exigent circumstances
exception “is likely to frustrate the governmental pur-
pose[s] behind [this] search.” Camara, 387 U. S., at 533.4
First, the Court cites the governmental interest in pro-
tecting the public from drunk drivers. See ante, at 24.
But it is critical to note that once a person is stopped for
drunk driving and arrested, he no longer poses an imme-
diate threat to the public. Because the person is already
in custody prior to the administration of the breath test,
there can be no serious claim that the time it takes to
obtain a warrant would increase the danger that drunk
driver poses to fellow citizens.
Second, the Court cites the governmental interest in
preventing the destruction or loss of evidence. See ante, at
30-31. But neither the Court nor the States identify any
practical reasons why obtaining a warrant after making
an arrest and before conducting a breath test compromises
the quality of the evidence obtained. To the contrary, the
delays inherent in administering reliable breath tests
——————
4 Although Bernard’s case arises in Minnesota, North Dakota’s simi-

lar breath test laws are before this Court. I therefore consider both
States together.
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Opinion of SOTOMAYOR, J.

generally provide ample time to obtain a warrant.
There is a common misconception that breath tests are
conducted roadside, immediately after a driver is arrested.
While some preliminary testing is conducted roadside,
reliability concerns with roadside tests confine their use in
most circumstances to establishing probable cause for an
arrest. See 2 R. Erwin, Defense of Drunk Driving Cases
§18.08 (3d ed. 2015) (“Screening devices are . . . used when
it is impractical to utilize an evidential breath tester
(EBT) (e.g. at roadside or at various work sites)”). The
standard evidentiary breath test is conducted after a
motorist is arrested and transported to a police station,
governmental building, or mobile testing facility where
officers can access reliable, evidence-grade breath testing
machinery. Brief for Respondent in No. 14–1618, p. 8,
n. 2; National Highway Transportation Safety Admin.
(NHTSA), A. Berning et al., Refusal of Intoxication Test-
ing: A Report to Congress 4, and n. 5 (No. 811098, Sept.
2008). Transporting the motorist to the equipment site is
not the only potential delay in the process, however.
Officers must also observe the subject for 15 to 20 minutes
to ensure that “residual mouth alcohol,” which can inflate
results and expose the test to an evidentiary challenge at
trial, has dissipated and that the subject has not inserted
any food or drink into his mouth.5 In many States, includ-
ing Minnesota, officers must then give the motorist a
window of time within which to contact an attorney before
administering a test.6 Finally, if a breath test machine is
——————
5 See NHTSA and International Assn. of Chiefs of Police, DWI Detec-
tion and Standardized Field Sobriety Testing Participant Guide,
Session 7, p. 20 (2013).
6 See Minn. Stat. §169A.51, subd. 2(4) (2014) (“[T]he person has the

right to consult with an attorney, but . . . this right is limited to the
extent that it cannot unreasonably delay administration of the test”);
see also Kuhn v. Commissioner of Public Safety, 488 N. W. 2d 838
(Minn. App. 1992) (finding 24 minutes insufficient time to contact an
 Cite as: 579 U. S. ____ (2016) 11

Opinion of SOTOMAYOR, J.

not already active, the police officer must set it up. North
Dakota’s Intoxilyzer 8000 machine can take as long as 30
minutes to “warm-up.”7
Because of these necessary steps, the standard breath
test is conducted well after an arrest is effectuated. The
Minnesota Court of Appeals has explained that nearly all
breath tests “involve a time lag of 45 minutes to two
hours.” State v. Larson, 429 N. W. 2d 674, 676 (Minn.
App. 1988); see also State v. Chirpich, 392 N. W. 2d 34, 37
(Minn. App. 1986). Both North Dakota and Minnesota
give police a 2-hour period from the time the motorist was
pulled over within which to administer a breath test.
N. D. Cent. Code Ann. §39–20–04.1(1) (2008); Minn. Stat.
§169A.20, subd. 1(5) (2014).8
During this built-in window, police can seek warrants.
That is particularly true in light of “advances” in technol-
ogy that now permit “the more expeditious processing of
warrant applications.” McNeely, 569 U. S., at ___–___, and
n. 4 (slip op., at 11–12, and n. 4) (describing increased
availability of telephonic warrants); Riley, 573 U. S., at
___ (slip op., at 26) (describing jurisdictions that have
adopted an e-mail warrant system that takes less than 15
minutes); Minn. Rules Crim. Proc. 33.05, 36.01–36.08
(2010 and Supp. 2013) (allowing telephonic warrants); N.
D. Rules Crim. Proc. 41(c)(2)–(3) (2013) (same). Moreover,

counsel for North Dakota explained at oral argument that

——————

attorney before being required to submit to a test).

7 See Office of Attorney General, Crime Lab. Div., Chemical Test

Training Student Manual, Fall 2011–Spring 2012, p. 13 (2011).
8 Many tests are conducted at the outer boundaries of that window.

See, e.g., Israel v. Commissioner of Public Safety, 400 N. W. 2d 428
(Minn. App. 1987) (57 minute poststop delay); Mosher v. Commissioner
of Public Safety, 2015 WL 3649344 (Minn. App., June 15, 2015) (119
minute postarrest delay); Johnson v. Commissioner of Public Safety,
400 N. W. 2d 195 (Minn. App. 1987) (96 minute postarrest delay);
Scheiterlein v. Commissioner of Public Safety, 2014 WL 3021278 (Minn.
App., July 7, 2014) (111 minute poststop delay).
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Opinion of SOTOMAYOR, J.

the State uses a typical “on-call” system in which some
judges are available even during off-duty times.9 See Tr.
of Oral Arg. 42.
Where “an officer can . . . secure a warrant while” the
motorist is being transported and the test is being pre-
pared, this Court has said that “there would be no plausi-
ble justification for an exception to the warrant require-
ment.” McNeely, 569 U. S., at ___ (slip op., at 10). Neither
the Court nor the States provide any evidence to suggest
that, in the normal course of affairs, obtaining a warrant
and conducting a breath test will exceed the allotted 2-
hour window.
Third, the Court and the States cite a governmental
interest in minimizing the costs of gathering evidence of
drunk driving. But neither has demonstrated that requir-
ing police to obtain warrants for breath tests would impose
a sufficiently significant burden on state resources to
justify the elimination of the Fourth Amendment’s war-
rant requirement. The Court notes that North Dakota has
82 judges and magistrate judges who are authorized to
issue warrants. See ante, at 27-28. Because North Da-
kota has roughly 7,000 drunk-driving arrests annually, the
Court concludes that if police were required to obtain
warrants “for every search incident to arrest that does not
involve exigent circumstances, the courts would be
swamped.” Ante, at 27. That conclusion relies on inflated
numbers and unsupported inferences.
Assuming that North Dakota police officers do not ob-
——————
9 Counsel for North Dakota represented at oral argument that in
“larger jurisdictions” it “takes about a half an hour” to obtain a war-
rant. Tr. of Oral Arg. 42. Counsel said that it is sometimes “harder to
get somebody on the phone” in rural jurisdictions, but even if it took
twice as long, the process of obtaining a warrant would be unlikely to
take longer than the inherent delays in preparing a motorist for testing
and would be particularly unlikely to reach beyond the 2-hour window
within which officers can conduct the test.
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Opinion of SOTOMAYOR, J.

tain warrants for any drunk-driving arrests today, and
assuming that they would need to obtain a warrant for
every drunk-driving arrest tomorrow, each of the State’s
82 judges and magistrate judges would need to issue fewer
than two extra warrants per week.10 Minnesota has nearly
the same ratio of judges to drunk-driving arrests, and so
would face roughly the same burden.11 These back-of-the-
envelope numbers suggest that the burden of obtaining a
warrant before conducting a breath test would be small in
both States.
But even these numbers overstate the burden by a sig-
nificant degree. States only need to obtain warrants for
drivers who refuse testing and a significant majority of
drivers voluntarily consent to breath tests, even in States
without criminal penalties for refusal. In North Dakota,
only 21% of people refuse breath tests and in Minnesota,
only 12% refuse. NHTSA, E. Namuswe, H. Coleman, & A.
Berning, Breath Test Refusal Rates in the United States–
2011 Update 2 (No. 811881 2014). Including States that
impose only civil penalties for refusal, the average refusal
rate is slightly higher at 24%. Id., at 3. Say that North
Dakota’s and Minnesota’s refusal rates rise to double the
mean, or 48%. Each of their judges and magistrate judges
would need to issue fewer than one extra warrant a
——————
10 Seven thousand annual arrests divided by 82 judges and magis-

trate judges is 85.4 extra warrants per judge and magistrate judge per
year. And 85.4 divided by 52 weeks is 1.64 extra warrants per judge
and magistrate judge per week.
11 Minnesota has about 25,000 drunk-driving incidents each year.

Minn. Dept. of Public Safety, Office of Traffic Safety, Minn. Impaired
Driving Facts 2014, p. 2 (2015). In Minnesota, all judges not exercising
probate jurisdiction can issue warrants. Minn. Stat. §626.06 (2009).
But the state district court judges appear to do the lion’s share of that
work. So, conservatively counting only those judges, the State has 280
judges that can issue warrants. Minnesota Judicial Branch, Report to
the Community 23 (2015). Similar to North Dakota, that amounts to
1.72 extra warrants per judge per week.
14 BIRCHFIELD v. NORTH DAKOTA

Opinion of SOTOMAYOR, J.

week.12 That bears repeating: The Court finds a categori-
cal exception to the warrant requirement because each of
a State’s judges and magistrate judges would need to issue
less than one extra warrant a week.
Fourth, the Court alludes to the need to collect evidence
conveniently. But mere convenience in investigating
drunk driving cannot itself justify an exception to the
warrant requirement. All of this Court’s postarrest excep-
tions to the warrant requirement require a law enforce-
ment interest separate from criminal investigation. The
Court’s justification for the search incident to arrest rule
is “the officer’s safety” and the prevention of evidence
“concealment or destruction.” Chimel, 395 U. S., at 763.
The Court’s justification for the booking exception, which
allows police to obtain fingerprints and DNA without a
warrant while booking an arrestee at the police station, is
the administrative need for identification. See Maryland
v. King, 569 U. S. ___, ___–___ (2013) (slip op., at 11–12).
The Court’s justification for the inventory search excep-
tion, which allows police to inventory the items in the
arrestee’s personal possession and car, is the need to
“protect an owner’s property while it is in the custody of
the police, to insure against claims of lost, stolen, or van-
dalized property, and to guard the police from danger.”
Colorado v. Bertine, 479 U. S. 367, 372 (1987).
This Court has never said that mere convenience in
gathering evidence justifies an exception to the warrant
requirement. See Florida v. Wells, 495 U. S. 1, 4 (1990)
(suppressing evidence where supposed “inventory” search
——————
12 Because each of North Dakota’s judges and magistrate judges

would have to issue an extra 1.64 warrants per week assuming a 100%
refusal rate, see supra, at 13, nn. 10–11, they would have to issue an
additional 0.79 per week assuming a 48% refusal rate. Adjusting for
the same conservatively high refusal rate, Minnesota would go from
1.72 additional warrants per judge per week to just 0.82.
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Opinion of SOTOMAYOR, J.

was done without standardized criteria, suggesting in-
stead “ ‘a purposeful and general means of discovering
evidence of crime’ ”). If the simple collection of evidence
justifies an exception to the warrant requirement even
where a warrant could be easily obtained, exceptions
would become the rule. Ibid.
Finally, as a general matter, the States have ample tools
to force compliance with lawfully obtained warrants. This
Court has never cast doubt on the States’ ability to impose
criminal penalties for obstructing a search authorized by a
lawfully obtained warrant. No resort to violent compli-
ance would be necessary to compel a test. If a police of-
ficer obtains a warrant to conduct a breath test, citizens
can be subjected to serious penalties for obstruction of
justice if they decline to cooperate with the test.
This Court has already taken the weighty step of char-
acterizing breath tests as “searches” for Fourth Amend-
ment purposes. See Skinner, 489 U. S., at 616–617. That
is because the typical breath test requires the subject to
actively blow alveolar (or “deep lung”) air into the ma-
chine. Ibid. Although the process of physically blowing
into the machine can be completed in as little as a few
minutes, the end-to-end process can be significantly longer.
The person administering the test must calibrate the
machine, collect at least two separate samples from the
arrestee, change the mouthpiece and reset the machine
between each, and conduct any additional testing indicated
by disparities between the two tests.13 Although some
searches are certainly more invasive than breath tests,
this Court cannot do justice to their status as Fourth
Amendment “searches” if exaggerated time pressures,
mere convenience in collecting evidence, and the “burden”
——————
13 See Office of Attorney General, Crime Lab. Div., Approved Method

To Conduct Breath Tests With the Intoxilyzer 8000 (BRS–001), pp. 4–6,
8 (2012).
16 BIRCHFIELD v. NORTH DAKOTA

Opinion of SOTOMAYOR, J.

of asking judges to issue an extra couple of warrants per
month are costs so high as to render reasonable a search
without a warrant.14 The Fourth Amendment becomes an
empty promise of protecting citizens from unreasonable
searches.
B
After evaluating the governmental and privacy interests
at stake here, the final step is to determine whether any
situations in which warrants would interfere with the
States’ legitimate governmental interests should be ac-
commodated through a case-by-case or categorical excep-
tion to the warrant requirement.
As shown, because there are so many circumstances in
which obtaining a warrant will not delay the administra-
tion of a breath test or otherwise compromise any govern-
mental interest cited by the States, it should be clear that
allowing a categorical exception to the warrant require-
ment is a “considerable overgeneralization” here.
McNeely, 569 U. S., at ___ (slip op., at 10). As this Court
concluded in Riley and McNeely, any unusual issues that
——————
14 In weighing the governmental interests at stake here, the Court

also downplays the “benefits” that warrants provide for breath tests.
Because this Court has said unequivocally that warrants are the usual
safeguard against unreasonable searches, see Katz v. United States,
389 U. S. 347, 357 (1967), the legal relevance of this discussion is not
clear. In any event, the Court is wrong to conclude that warrants
provide little benefit here. The Court says that any warrants for breath
tests would be issued based on the “characterization” of the police
officer, which a “magistrate would be in a poor position to challenge.”
Ante, at 29. Virtually all warrants will rely to some degree on an
officer’s own perception. The very purpose of warrants is to have a
neutral arbiter determine whether inferences drawn from officers’
perceptions and circumstantial evidence are sufficient to justify a
search. Regardless of the particulars, the Court’s mode of analysis is a
dangerous road to venture down. Historically, our default has been
that warrants are required. This part of the Court’s argument instead
suggests, without precedent, that their value now has to be proven.
 Cite as: 579 U. S. ____ (2016) 17

Opinion of SOTOMAYOR, J.

do arise can “better [be] addressed through considera-
tion of case-specific exceptions to the warrant require-
ment.” Riley, 573 U. S., at ___ (slip op., at 11); see also
McNeely, 569 U. S., at ___ (slip op., at 15) (opinion of
SOTOMAYOR, J.).
Without even considering the comparative effectiveness
of case-by-case and categorical exceptions, the Court
reaches for the categorical search-incident-to-arrest excep-
tion and enshrines it for all breath tests. The majority
apparently assumes that any postarrest search should be
analyzed under the search-incident-to-arrest doctrine. See
ante, at 16 (“In the three cases now before us, the drivers
were searched or told that they were required to submit to
a search after being placed under arrest for drunk driving.
We therefore consider how the search-incident-to-arrest
doctrine applies to breath and blood tests incident to such
arrests”).
But, as we explained earlier, police officers may want to
conduct a range of different searches after placing a per-
son under arrest. Each of those searches must be sepa-
rately analyzed for Fourth Amendment compliance. Two
narrow types of postarrest searches are analyzed together
under the rubric of our search-incident-to-arrest doctrine:
Searches to disarm arrestees who could pose a danger
before a warrant is obtained and searches to find evidence
arrestees have an incentive to destroy before a warrant is
obtained. Chimel, 395 U. S., at 763. Other forms of
postarrest searches are analyzed differently because they
present needs that require more tailored exceptions to the
warrant requirement. See supra, at 4–5 (discussing
postarrest application of the “exigency” exception); see also
supra, at 13–14 (discussing postarrest booking and inven-
tory exceptions).
The fact that a person is under arrest does not tell us
which of these warrant exceptions should apply to a par-
ticular kind of postarrest search. The way to analyze
18 BIRCHFIELD v. NORTH DAKOTA

Opinion of SOTOMAYOR, J.

which exception, if any, is appropriate is to ask whether
the exception best addresses the nature of the postarrest
search and the needs it fulfills. Yet the majority never
explains why the search-incident-to-arrest framework—its
justifications, applications, and categorical scope—is best
suited to breath tests.
To the contrary, the search-incident-to-arrest exception
is particularly ill suited to breath tests. To the extent the
Court discusses any fit between breath tests and the
rationales underlying the search-incident-to-arrest excep-
tion, it says that evidence preservation is one of the core
values served by the exception and worries that “evidence
may be lost” if breath tests are not conducted. Ante, at 31.
But, of course, the search-incident-to-arrest exception is
concerned with evidence destruction only insofar as that
destruction would occur before a warrant could be sought.
And breath tests are not, except in rare circumstances,
conducted at the time of arrest, before a warrant can be
obtained, but at a separate location 40 to 120 minutes
after an arrest is effectuated. That alone should be reason
to reject an exception forged to address the immediate
needs of arrests.
The exception’s categorical reach makes it even less
suitable here. The search-incident-to-arrest exception is
applied categorically precisely because the needs it ad-
dresses could arise in every arrest. Robinson, 414 U. S., at
236. But the government’s need to conduct a breath test is
present only in arrests for drunk driving. And the asserted
need to conduct a breath test without a warrant arises
only when a warrant cannot be obtained during the signif-
icant built-in delay between arrest and testing. The condi-
tions that require warrantless breath searches, in short,
are highly situational and defy the logical underpinnings
of the search-incident-to-arrest exception and its categori-
cal application.
 Cite as: 579 U. S. ____ (2016) 19

Opinion of SOTOMAYOR, J.

* * *
In Maryland v. King, this Court dispensed with the
warrant requirement and allowed DNA searches following
an arrest. But there, it at least attempted to justify the
search using the booking exception’s interest in identifying
arrestees. 569 U. S., at ___–___ (slip op., at 11–18); id., at
___–___ (slip op., at 4–6) (Scalia, J., dissenting). Here, the
Court lacks even the pretense of attempting to situate
breath searches within the narrow and weighty law en-
forcement needs that have historically justified the limited
use of warrantless searches. I fear that if the Court con-
tinues down this road, the Fourth Amendment’s warrant
requirement will become nothing more than a suggestion.
 Cite as: 579 U. S. ____ (2016) 1

THOMAS, J., concurring
Opinionin
ofpart and,dissenting
THOMAS J. in part

SUPREME COURT OF THE UNITED STATES
_________________

Nos. 14–1468, 14–1470, and 14–1507
_________________

DANNY BIRCHFIELD, PETITIONER
14–1468 v.
NORTH DAKOTA;
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

NORTH DAKOTA

WILLIAM ROBERT BERNARD, JR., PETITIONER
14–1470 v.
MINNESOTA; AND
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

MINNESOTA

STEVE MICHAEL BEYLUND, PETITIONER
14–1507 v.
GRANT LEVI, DIRECTOR, NORTH DAKOTA
DEPARTMENT OF TRANSPORTATION
ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

NORTH DAKOTA

[June 23, 2016]

JUSTICE THOMAS, concurring in judgment in part and
dissenting in part.
The compromise the Court reaches today is not a good
one. By deciding that some (but not all) warrantless tests
revealing the blood alcohol concentration (BAC) of an
arrested driver are constitutional, the Court contorts the
search-incident-to-arrest exception to the Fourth Amend-
ment’s warrant requirement. The far simpler answer to
2 BIRCHFIELD v. NORTH DAKOTA

THOMAS, J., concurring
Opinionin
ofpart and,dissenting
THOMAS J. in part

the question presented is the one rejected in Missouri v.
McNeely, 569 U. S. ___ (2013). Here, the tests revealing
the BAC of a driver suspected of driving drunk are consti-
tutional under the exigent-circumstances exception to the
warrant requirement. Id., at ___–___ (THOMAS, J., dis-
senting) (slip op., at 3–4).
I
Today’s decision chips away at a well-established excep-
tion to the warrant requirement. Until recently, we have
admonished that “[a] police officer’s determination as to
how and where to search the person of a suspect whom he
has arrested is necessarily a quick ad hoc judgment which
the Fourth Amendment does not require to be broken
down in each instance into an analysis of each step in the
search.” United States v. Robinson, 414 U. S. 218, 235
(1973). Under our precedents, a search incident to lawful
arrest “require[d] no additional justification.” Ibid. Not
until the recent decision in Riley v. California, 573 U. S.
___ (2014), did the Court begin to retreat from this cate-
gorical approach because it feared that the search at issue,
the “search of the information on a cell phone,” bore “little
resemblance to the type of brief physical search” contem-
plated by this Court’s past search-incident-to-arrest deci-
sions. Id., at ___ (slip op., at 10). I joined Riley, however,
because the Court resisted the temptation to permit
searches of some kinds of cell-phone data and not others,
id., at ___–___ (slip op., at 23–25), and instead asked more
generally whether that entire “category of effects” was
searchable without a warrant, id., at ___ (slip op., at 10).
Today’s decision begins where Riley left off. The Court
purports to apply Robinson but further departs from its
categorical approach by holding that warrantless breath
tests to prevent the destruction of BAC evidence are con-
stitutional searches incident to arrest, but warrantless
blood tests are not. Ante, at 35 (“Because breath tests are
 Cite as: 579 U. S. ____ (2016) 3

THOMAS, J., concurring
Opinionin
ofpart and,dissenting
THOMAS J. in part

significantly less intrusive than blood tests and in most
cases amply serve law enforcement interests, we conclude
that a breath test, but not a blood test, may be adminis-
tered as a search incident to a lawful arrest for drunk
driving”). That hairsplitting makes little sense. Either
the search-incident-to-arrest exception permits bodily
searches to prevent the destruction of BAC evidence, or it
does not.
The Court justifies its result—an arbitrary line in the
sand between blood and breath tests—by balancing the
invasiveness of the particular type of search against the
government’s reasons for the search. Ante, at 20–36.
Such case-by-case balancing is bad for the People, who
“through ratification, have already weighed the policy
tradeoffs that constitutional rights entail.” Luis v. United
States, 578 U. S. ___, ___ (2016) (THOMAS, J., concurring in
judgment) (slip op., at 10); see also Crawford v. Washing-
ton, 541 U. S. 36, 67–68 (2004). It is also bad for law
enforcement officers, who depend on predictable rules to
do their job, as Members of this Court have exhorted in
the past. See Arizona v. Gant, 556 U. S. 332, 359 (2009)
(ALITO, J., dissenting); see also id., at 363 (faulting the
Court for “leav[ing] the law relating to searches incident to
arrest in a confused and unstable state”).
Today’s application of the search-incident-to-arrest
exception is bound to cause confusion in the lower courts.
The Court’s choice to allow some (but not all) BAC searches
is undeniably appealing, for it both reins in the perni-
cious problem of drunk driving and also purports to pre-
serve some Fourth Amendment protections. But that
compromise has little support under this Court’s existing
precedents.
II
The better (and far simpler) way to resolve these cases
is by applying the per se rule that I proposed in McNeely.
4 BIRCHFIELD v. NORTH DAKOTA

THOMAS, J., concurring
Opinionin
ofpart and,dissenting
THOMAS J. in part

Under that approach, both warrantless breath and blood
tests are constitutional because “the natural metaboliza-
tion of [BAC] creates an exigency once police have proba-
ble cause to believe the driver is drunk. It naturally fol-
lows that police may conduct a search in these
circumstances.” 569 U. S., at ___–___ (dissenting opinion)
(slip op., at 3–4).
The Court in McNeely rejected that bright-line rule and
instead adopted a totality-of-the-circumstances test exam-
ining whether the facts of a particular case presented
exigent circumstances justifying a warrantless search.
Id., at ___ (slip op., at 1). The Court ruled that “the natu-
ral dissipation of alcohol in the blood” could not “categori-
cally” create an “exigency” in every case. Id., at ___ (slip
op., at 13). The destruction of “BAC evidence from a
drunk-driving suspect” that “naturally dissipates over
time in a gradual and relatively predictable manner,”
according to the Court, was qualitatively different from
the destruction of evidence in “circumstances in which the
suspect has control over easily disposable evidence.” Id.,
at ___ (slip op., at 10).
Today’s decision rejects McNeely’s arbitrary distinction
between the destruction of evidence generally and the
destruction of BAC evidence. But only for searches inci-
dent to arrest. Ante, at 31–33. The Court declares that
such a distinction “between an arrestee’s active destruc-
tion of evidence and the loss of evidence due to a natural
process makes little sense.” Ante, at 31. I agree. See
McNeely, supra, at ___–___ (THOMAS, J., dissenting) (slip
op., at 5–6). But it also “makes little sense” for the Court
to reject McNeely’s arbitrary distinction only for searches
incident to arrest and not also for exigent-circumstances
searches when both are justified by identical concerns
about the destruction of the same evidence. McNeely’s
distinction is no less arbitrary for searches justified by
exigent circumstances than those justified by search inci-
 Cite as: 579 U. S. ____ (2016) 5

THOMAS, J., concurring
Opinionin
ofpart and,dissenting
THOMAS J. in part

dent to arrest.
The Court was wrong in McNeely, and today’s compro-
mise is perhaps an inevitable consequence of that error.
Both searches contemplated by the state laws at issue in
these cases would be constitutional under the exigent-
circumstances exception to the warrant requirement. I
respectfully concur in the judgment in part and dissent in
part.