Porter v. McCollum

Cite as: 558 U. S. ____ (2009) 1

Per Curiam

SUPREME COURT OF THE UNITED STATES
GEORGE PORTER, JR. v. BILL MCCOLLUM,
ATTORNEY GENERAL OF FLORIDA, ET AL.
ON PETITION FOR WRIT OF CERTIORARI TO THE UNITED

STATES COURT OF APPEALS FOR THE ELEVENTH CIRCUIT

No. 08–10537. Decided November 30, 2009

PER CURIAM.
Petitioner George Porter is a veteran who was both
wounded and decorated for his active participation in two
major engagements during the Korean War; his combat
service unfortunately left him a traumatized, changed
man. His commanding officer’s moving description of
those two battles was only a fraction of the mitigating
evidence that his counsel failed to discover or present
during the penalty phase of his trial in 1988.
In this federal postconviction proceeding, the District
Court held that Porter’s lawyer’s failure to adduce that
evidence violated his Sixth Amendment right to counsel
and granted his application for a writ of habeas corpus.
The Court of Appeals for the Eleventh Circuit reversed, on
the ground that the Florida Supreme Court’s determina
tion that Porter was not prejudiced by any deficient per
formance by his counsel was a reasonable application of
Strickland v. Washington, 466 U. S. 668 (1984). Like the
District Court, we are persuaded that it was objectively
unreasonable to conclude there was no reasonable prob
ability the sentence would have been different if the sen
tencing judge and jury had heard the significant mitiga
tion evidence that Porter’s counsel neither uncovered nor
presented. We therefore grant the petition for certiorari in
part and reverse the judgment of the Court of Appeals.1

——————
1 We deny the petition insofar as it challenges his conviction.
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I
Porter was convicted of two counts of first-degree mur
der for the shooting of his former girlfriend, Evelyn Wil
liams, and her boyfriend Walter Burrows. He was sen
tenced to death on the first count but not the second.
In July 1986, as his relationship with Williams was
ending, Porter threatened to kill her and then left town.
When he returned to Florida three months later, he at
tempted to see Williams but her mother told him that
Williams did not want to see him. He drove past Williams’
house each of the two days prior to the shooting, and the
night before the murder he visited Williams, who called
the police. Porter then went to two cocktail lounges and
spent the night with a friend, who testified Porter was
quite drunk by 11 p.m. Early the next morning, Porter
shot Williams in her house. Burrows struggled with Por
ter and forced him outside where Porter shot him.
Porter represented himself, with standby counsel, for
most of the pretrial proceedings and during the beginning
of his trial. Near the completion of the State’s case in
chief, Porter pleaded guilty. He thereafter changed his
mind about representing himself, and his standby counsel
was appointed as his counsel for the penalty phase. Dur
ing the penalty phase, the State attempted to prove four
aggravating factors: Porter had been “previously con
victed” of another violent felony (i.e., in Williams’ case,
killing Burrows, and in his case, killing Williams);2 the
murder was committed during a burglary; the murder was
committed in a cold, calculated, and premeditated man
——————
2 It is an aggravating factor under Florida law that “[t]he defendant

was previously convicted of another capital felony or of a felony involv
ing the use or threat of violence to the person.” Fla. Stat.
§921.141(5)(b) (1987). In Porter’s case, the State established that factor
by reference to Porter’s contemporaneous convictions stemming from
the same episode: two counts of murder and one count of aggravated
assault. Tr. 5 (Mar. 4, 1988).
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Per Curiam

ner; and the murder was especially heinous, atrocious, or
cruel. The defense put on only one witness, Porter’s ex
wife, and read an excerpt from a deposition. The sum
total of the mitigating evidence was inconsistent testi
mony about Porter’s behavior when intoxicated and testi
mony that Porter had a good relationship with his son.
Although his lawyer told the jury that Porter “has other
handicaps that weren’t apparent during the trial” and
Porter was not “mentally healthy,” he did not put on any
evidence related to Porter’s mental health. 3 Tr. 477–478
(Jan. 22, 1988).
The jury recommended the death sentence for both
murders. The trial court found that the State had proved
all four aggravating circumstances for the murder of
Williams but that only the first two were established with
respect to Burrows’ murder. The trial court found no
mitigating circumstances and imposed a death sentence
for Williams’ murder only. On direct appeal, the Florida
Supreme Court affirmed the sentence over the dissent of
two justices, but struck the heinous, atrocious, or cruel
aggravating factor. Porter v. State, 564 So. 2d 1060 (1990)
(per curiam). The court found the State had not carried its
burden on that factor because the “record is consistent
with the hypothesis that Porter’s was a crime of passion,
not a crime that was meant to be deliberately and ex
traordinarily painful.” Id., at 1063 (emphasis deleted).
The two dissenting justices would have reversed the pen
alty because the evidence of drunkenness, “combined with
evidence of Porter’s emotionally charged, desperate, frus
trated desire to meet with his former lover, is sufficient to
render the death penalty disproportional punishment in
this instance.” Id., at 1065–1066 (Barkett, J., concurring
in part and dissenting in part).
In 1995, Porter filed a petition for postconviction relief
in state court, claiming his penalty-phase counsel failed to
investigate and present mitigating evidence. The court
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conducted a 2-day evidentiary hearing, during which
Porter presented extensive mitigating evidence, all of
which was apparently unknown to his penalty-phase
counsel. Unlike the evidence presented during Porter’s
penalty hearing, which left the jury knowing hardly any
thing about him other than the facts of his crimes, the new
evidence described his abusive childhood, his heroic mili
tary service and the trauma he suffered because of it, his
long-term substance abuse, and his impaired mental
health and mental capacity.
The depositions of his brother and sister described the
abuse Porter suffered as a child. Porter routinely wit
nessed his father beat his mother, one time so severely
that she had to go to the hospital and lost a child. Porter’s
father was violent every weekend, and by his siblings’
account, Porter was his father’s favorite target, particu
larly when Porter tried to protect his mother. On one
occasion, Porter’s father shot at him for coming home late,
but missed and just beat Porter instead. According to his
brother, Porter attended classes for slow learners and left
school when he was 12 or 13.
To escape his horrible family life, Porter enlisted in the
Army at age 17 and fought in the Korean War. His com
pany commander, Lieutenant Colonel Sherman Pratt,
testified at Porter’s postconviction hearing. Porter was
with the 2d Division, which had advanced above the 38th
parallel to Kunu-ri when it was attacked by Chinese
forces. Porter suffered a gunshot wound to the leg during
the advance but was with the unit for the battle at Kunu
ri. While the Eighth Army was withdrawing, the 2d Divi
sion was ordered to hold off the Chinese advance, enabling
the bulk of the Eighth Army to live to fight another day.
As Colonel Pratt described it, the unit “went into position
there in bitter cold night, terribly worn out, terribly
weary, almost like zombies because we had been in con
stant—for five days we had been in constant contact with
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Per Curiam

the enemy fighting our way to the rear, little or no sleep,
little or no food, literally as I say zombies.” 1 Tr. 138 (Jan.
4, 1996). The next morning, the unit engaged in a “fierce
hand-to-hand fight with the Chinese” and later that day
received permission to withdraw, making Porter’s regi
ment the last unit of the Eighth Army to withdraw. Id., at
139–140.
Less than three months later, Porter fought in a second
battle, at Chip’yong-ni. His regiment was cut off from the
rest of the Eighth Army and defended itself for two days
and two nights under constant fire. After the enemy broke
through the perimeter and overtook defensive positions on
high ground, Porter’s company was charged with retaking
those positions. In the charge up the hill, the soldiers
“were under direct open fire of the enemy forces on top of
the hill. They immediately came under mortar, artillery,
machine gun, and every other kind of fire you can imagine
and they were just dropping like flies as they went along.”
Id., at 150. Porter’s company lost all three of its platoon
sergeants, and almost all of the officers were wounded.
Porter was again wounded and his company sustained the
heaviest losses of any troops in the battle, with more than
50% casualties. Colonel Pratt testified that these battles
were “very trying, horrifying experiences,” particularly for
Porter’s company at Chip’yong-ni. Id., at 152. Porter’s
unit was awarded the Presidential Unit Citation for the
engagement at Chip’yong-ni, and Porter individually
received two Purple Hearts and the Combat Infantryman
Badge, along with other decorations.
Colonel Pratt testified that Porter went absent without
leave (AWOL) for two periods while in Korea. He ex
plained that this was not uncommon, as soldiers some
times became disoriented and separated from the unit,
and that the commander had decided not to impose any
punishment for the absences. In Colonel Pratt’s experi
ence, an “awful lot of [veterans] come back nervous
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Per Curiam

wrecks. Our [veterans’] hospitals today are filled with
people mentally trying to survive the perils and hardships
[of] . . . the Korean War,” particularly those who fought in
the battles he described. Id., at 153.
When Porter returned to the United States, he went
AWOL for an extended period of time.3 He was sentenced
to six months’ imprisonment for that infraction, but he
received an honorable discharge. After his discharge, he
suffered dreadful nightmares and would attempt to climb
his bedroom walls with knives at night.4 Porter’s family
eventually removed all of the knives from the house.
According to Porter’s brother, Porter developed a serious
drinking problem and began drinking so heavily that he
would get into fights and not remember them at all.
In addition to this testimony regarding his life history,
Porter presented an expert in neuropsychology, Dr. Dee,
who had examined Porter and administered a number of
psychological assessments. Dr. Dee concluded that Porter
suffered from brain damage that could manifest in impul
sive, violent behavior. At the time of the crime, Dr. Dee
testified, Porter was substantially impaired in his ability
to conform his conduct to the law and suffered from an
extreme mental or emotional disturbance, two statutory
mitigating circumstances, Fla. Stat. §921.141(6). Dr. Dee
also testified that Porter had substantial difficulties with
——————
3 Porter explained to one of the doctors who examined him for compe

tency to stand trial that he went AWOL in order to spend time with his
son. Record 904.
4 Porter’s expert testified that these symptoms would “easily” warrant

a diagnosis of posttraumatic stress disorder (PTSD). 2 Tr. 233 (Jan. 5,
1996). PTSD is not uncommon among veterans returning from combat.
See Hearing on Fiscal Year 2010 Budget for Veterans’ Programs before
the Senate Committee on Veterans’ Affairs, 111th Cong., 1st Sess., 63
(2009) (uncorrected copy) (testimony of Eric K. Shinseki, Secretary of
Veterans Affairs (VA), reporting that approximately 23 percent of the
Iraq and Afghanistan war veterans seeking treatment at a VA medical
facility had been preliminarily diagnosed with PTSD).
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Per Curiam

reading, writing, and memory, and that these cognitive
defects were present when he was evaluated for compe
tency to stand trial. 2 Tr. 227–228 (Jan. 5, 1996); see also
Record 904–906. Although the State’s experts reached
different conclusions regarding the statutory mitigators,5
each expert testified that he could not diagnose Porter or
rule out a brain abnormality. 2 Tr. 345, 382 (Jan. 5,
1996); 3 id., at 405.
The trial judge who conducted the state postconviction
hearing, without determining counsel’s deficiency, held
that Porter had not been prejudiced by the failure to in
troduce any of that evidence. Record 1203, 1206. He
found that Porter had failed to establish any statutory
mitigating circumstances, id., at 1207, and that the non
statutory mitigating evidence would not have made a
difference in the outcome of the case, id., at 1210. He
discounted the evidence of Porter’s alcohol abuse because
it was inconsistent and discounted the evidence of Porter’s
abusive childhood because he was 54 years old at the time
of the trial. He also concluded that Porter’s periods of
being AWOL would have reduced the impact of Porter’s
military service to “inconsequential proportions.” Id., at
1212. Finally, he held that even considering all three
categories of evidence together, the “trial judge and jury
still would have imposed death.” Id., at 1214.
The Florida Supreme Court affirmed. It first accepted
the trial court’s finding that Porter could not have estab
lished any statutory mitigating circumstances, based on
the trial court’s acceptance of the State’s experts’ conclu
sions in that regard. Porter v. State, 788 So. 2d 917, 923
(2001) (per curiam). It then held the trial court was cor

——————
5 The State presented two experts, Dr. Riebsame and Dr. Kirkland.
Neither of the State’s experts had examined Porter, but each testified
that based upon their review of the record, Porter met neither statutory
mitigating circumstance.
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rect to find “the additional nonstatutory mitigation to be
lacking in weight because of the specific facts presented.”
Id., at 925. Like the postconviction court, the Florida
Supreme Court reserved judgment regarding counsel’s
deficiency. Ibid.6 Two justices dissented, reasoning that
counsel’s failure to investigate and present mitigating
evidence was “especially harmful” because of the divided
vote affirming the sentence on direct appeal—“even with
out the substantial mitigation that we now know ex
isted”—and because of the reversal of the heinous, atro
cious, and cruel aggravating factor. Id., at 937 (Anstead,
J., concurring in part and dissenting in part).
Porter thereafter filed his federal habeas petition. The
District Court held Porter’s penalty-phase counsel had
been ineffective. It first determined that counsel’s per
formance had been deficient because “penalty-phase coun
sel did little, if any investigation . . . and failed to effec
tively advocate on behalf of his client before the jury.”
Porter v. Crosby, No. 6:03–cv–1465–Orl–31KRS, 2007 WL
1747316, *23 (MD Fla., June 18, 2007). It then deter
mined that counsel’s deficient performance was prejudi
cial, finding that the state court’s decision was contrary to
clearly established law in part because the state court
failed to consider the entirety of the evidence when re
——————
6 The postconviction court stated defense counsel “was not ineffective

for failing to pursue mental health evaluations and . . . [Porter] has
thus failed to show sufficient evidence that any statutory mitigators
could have been presented.” Record 1210. It is not at all clear whether
this stray comment addressed counsel’s deficiency. If it did, then it was
at most dicta, because the court expressly “decline[d] to make a deter
mination regarding whether or not Defense Counsel was in fact defi
cient here.” Id., at 1206. The Florida Supreme Court simply para
phrased the postconviction court when it stated “trial counsel’s decision
not to pursue mental evaluations did not exceed the bounds for compe
tent counsel.” Porter v. State, 788 So. 2d 917, 923–924 (2001) (per
curiam). But that court also expressly declined to answer the question
of deficiency. Id., at 925.
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weighing the evidence in mitigation, including the trial
evidence suggesting that “this was a crime of passion, that
[Porter] was drinking heavily just hours before the mur
ders, or that [Porter] had a good relationship with his
son.” Id., at *30.
The Eleventh Circuit reversed. It held the District
Court had failed to appropriately defer to the state court’s
factual findings with respect to Porter’s alcohol abuse and
his mental health. 552 F. 3d 1260, 1274, 1275 (2008) (per
curiam). The Court of Appeals then separately considered
each category of mitigating evidence and held it was not
unreasonable for the state court to discount each category
as it did. Id., at 1274. Porter petitioned for a writ of
certiorari. We grant the petition and reverse with respect
to the Court of Appeals’ disposition of Porter’s ineffective-
assistance claim.
II
To prevail under Strickland, Porter must show that his
counsel’s deficient performance prejudiced him. To estab
lish deficiency, Porter must show his “counsel’s represen
tation fell below an objective standard of reasonableness.”
466 U. S., at 688. To establish prejudice, he “must show
that there is a reasonable probability that, but for coun
sel’s unprofessional errors, the result of the proceeding
would have been different.” Id., at 694. Finally, Porter is
entitled to relief only if the state court’s rejection of his
claim of ineffective assistance of counsel was “contrary to,
or involved an unreasonable application of” Strickland, or
it rested “on an unreasonable determination of the facts in
light of the evidence presented in the State court proceed
ing.” 28 U. S. C. §2254(d).
Because the state court did not decide whether Porter’s
counsel was deficient, we review this element of Porter’s
Strickland claim de novo. Rompilla v. Beard, 545 U. S.
374, 390 (2005). It is unquestioned that under the prevail
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ing professional norms at the time of Porter’s trial, counsel
had an “obligation to conduct a thorough investigation of
the defendant’s background.” Williams v. Taylor, 529
U. S. 362, 396 (2000). The investigation conducted by
Porter’s counsel clearly did not satisfy those norms.
Although Porter had initially elected to represent him
self, his standby counsel became his counsel for the pen
alty phase a little over a month prior to the sentencing
proceeding before the jury. It was the first time this law
yer had represented a defendant during a penalty-phase
proceeding. At the postconviction hearing, he testified
that he had only one short meeting with Porter regarding
the penalty phase. He did not obtain any of Porter’s
school, medical, or military service records or interview
any members of Porter’s family. In Wiggins v. Smith, 539
U. S. 510, 524, 525 (2003), we held counsel “fell short of
. . . professional standards” for not expanding their inves
tigation beyond the presentence investigation report and
one set of records they obtained, particularly “in light of
what counsel actually discovered” in the records. Here,
counsel did not even take the first step of interviewing
witnesses or requesting records. Cf. Bobby v. Van Hook,
ante, at 6–8 (holding performance not deficient when
counsel gathered a substantial amount of information and
then made a reasonable decision not to pursue additional
sources); Strickland, 466 U. S., at 699 (“[Counsel’s] deci
sion not to seek more character or psychological evidence
than was already in hand was . . . reasonable”). Beyond
that, like the counsel in Wiggins, he ignored pertinent
avenues for investigation of which he should have been
aware. The court-ordered competency evaluations, for
example, collectively reported Porter’s very few years of
regular school, his military service and wounds sustained
in combat, and his father’s “over-disciplin[e].” Record
902–906. As an explanation, counsel described Porter as
fatalistic and uncooperative. But he acknowledged that
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although Porter instructed him not to speak with Porter’s
ex-wife or son, Porter did not give him any other instruc
tions limiting the witnesses he could interview.
Counsel thus failed to uncover and present any evidence
of Porter’s mental health or mental impairment, his family
background, or his military service. The decision not to
investigate did not reflect reasonable professional judg
ment. Wiggins, supra, at 534. Porter may have been
fatalistic or uncooperative, but that does not obviate the
need for defense counsel to conduct some sort of mitigation
investigation. See Rompilla, supra, at 381–382.
III
Because we find Porter’s counsel deficient, we must
determine whether the Florida Supreme Court unrea
sonably applied Strickland in holding Porter was not
prejudiced by that deficiency. Under Strickland, a defen
dant is prejudiced by his counsel’s deficient performance if
“there is a reasonable probability that, but for counsel’s
unprofessional errors, the result of the proceeding would
have been different.” 466 U. S., at 694. In Florida, the
sentencing judge makes the determination as to the exis
tence and weight of aggravating and mitigating circum
stances and the punishment, Fla. Stat. §921.141(3), but he
must give the jury verdict of life or death “great weight,”
Tedder v. State, 322 So. 2d 908, 910 (Fla. 1975) (per cu
riam). Porter must show that but for his counsel’s defi
ciency, there is a reasonable probability he would have
received a different sentence. To assess that probability,
we consider “the totality of the available mitigation evi
dence—both that adduced at trial, and the evidence ad
duced in the habeas proceeding”—and “reweig[h] it
against the evidence in aggravation.” Williams, supra, at
397–398.
This is not a case in which the new evidence “would
barely have altered the sentencing profile presented to the
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sentencing judge.” Strickland, supra, at 700. The judge
and jury at Porter’s original sentencing heard almost
nothing that would humanize Porter or allow them to
accurately gauge his moral culpability. They learned
about Porter’s turbulent relationship with Williams, his
crimes, and almost nothing else. Had Porter’s counsel
been effective, the judge and jury would have learned of
the “kind of troubled history we have declared relevant to
assessing a defendant’s moral culpability.” Wiggins, su
pra, at 535. They would have heard about (1) Porter’s
heroic military service in two of the most critical—and
horrific—battles of the Korean War, (2) his struggles to
regain normality upon his return from war, (3) his child
hood history of physical abuse, and (4) his brain abnormal
ity, difficulty reading and writing, and limited schooling.
See Penry v. Lynaugh, 492 U. S. 302, 219 (1989)
(“ ‘[E]vidence about the defendant’s background and char
acter is relevant because of the belief, long held by this
society, that defendants who commit criminal acts that are
attributable to a disadvantaged background . . . may be
less culpable’ ”). Instead, they heard absolutely none of
that evidence, evidence which “might well have influenced
the jury’s appraisal of [Porter’s] moral culpability.” Wil
liams, 529 U. S., at 398.
On the other side of the ledger, the weight of evidence in
aggravation is not as substantial as the sentencing judge
thought. As noted, the sentencing judge accepted the
jury’s recommendation of a death sentence for the murder
of Williams but rejected the jury’s death-sentence recom
mendation for the murder of Burrows. The sentencing
judge believed that there were four aggravating circum
stances related to the Williams murder but only two for
the Burrows murder. Accordingly, the judge must have
reasoned that the two aggravating circumstances that
were present in both cases were insufficient to warrant a
death sentence but that the two additional aggravating
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circumstances present with respect to the Williams mur
der were sufficient to tip the balance in favor of a death
sentence. But the Florida Supreme Court rejected one of
these additional aggravating circumstances, i.e., that
Williams’ murder was especially heinous, atrocious, or
cruel, finding the murder “consistent with . . . a crime of
passion” even though premeditated to a heightened de
gree. 564 So. 2d, at 1063–1064. Had the judge and jury
been able to place Porter’s life history “on the mitigating
side of the scale,” and appropriately reduced the ballast on
the aggravating side of the scale, there is clearly a reason
able probability that the advisory jury—and the sentenc
ing judge—“would have struck a different balance,” Wig
gins, 539 U. S., at 537, and it is unreasonable to conclude
otherwise.
The Florida Supreme Court’s decision that Porter was
not prejudiced by his counsel’s failure to conduct a thor
ough—or even cursory—investigation is unreasonable.
The Florida Supreme Court either did not consider or
unreasonably discounted the mitigation evidence adduced
in the postconviction hearing. Under Florida law, mental
health evidence that does not rise to the level of establish
ing a statutory mitigating circumstance may nonetheless
be considered by the sentencing judge and jury as mitigat
ing. See, e.g., Hoskins v. State, 965 So. 2d 1, 17–18 (Fla.
2007) (per curiam). Indeed, the Constitution requires that
“the sentencer in capital cases must be permitted to con
sider any relevant mitigating factor.” Eddings v. Okla
homa, 455 U. S. 104, 112 (1982). Yet neither the postcon
viction trial court nor the Florida Supreme Court gave any
consideration for the purpose of nonstatutory mitigation to
Dr. Dee’s testimony regarding the existence of a brain
abnormality and cognitive defects.7 While the State’s
——————
7 The Florida Supreme Court acknowledged that Porter had pre

sented evidence of “statutory and nonstatutory mental mitigation,” 788
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experts identified perceived problems with the tests that
Dr. Dee used and the conclusions that he drew from them,
it was not reasonable to discount entirely the effect that
his testimony might have had on the jury or the sentenc
ing judge.
Furthermore, the Florida Supreme Court, following the
state postconviction court, unreasonably discounted the
evidence of Porter’s childhood abuse and military service.
It is unreasonable to discount to irrelevance the evidence
of Porter’s abusive childhood, especially when that kind of
history may have particular salience for a jury evaluating
Porter’s behavior in his relationship with Williams. It is
also unreasonable to conclude that Porter’s military ser
vice would be reduced to “inconsequential proportions,”
788 So. 2d, at 925, simply because the jury would also
have learned that Porter went AWOL on more than one
occasion. Our Nation has a long tradition of according
leniency to veterans in recognition of their service, espe
cially for those who fought on the front lines as Porter
did.8 Moreover, the relevance of Porter’s extensive combat
experience is not only that he served honorably under
extreme hardship and gruesome conditions, but also that
the jury might find mitigating the intense stress and
mental and emotional toll that combat took on Porter.9
——————
So. 2d, at 921, but it did not consider Porter’s mental health evidence in
its discussion of nonstatutory mitigating evidence, id., at 924.
8 See Abbott, The Civil War and the Crime Wave of 1865–70, 1 Soc.

Serv. Rev. 212, 232–234 (1927) (discussing the movement to pardon or
parole prisoners who were veterans of the Civil War); Rosenbaum, The
Relationship Between War and Crime in the United States, 30 J. Crim.
L. & C. 722, 733–734 (1940) (describing a 1922 study by the Wisconsin
Board of Control that discussed the number of veterans imprisoned in
the State and considered “the greater leniency that may be shown to ex
service men in court”).
9 Cf. Cal. Penal Code Ann. §1170.9(a) (West Supp. 2009) (providing a

special hearing for a person convicted of a crime “who alleges that he or
she committed the offense as a result of post-traumatic stress disorder,
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The evidence that he was AWOL is consistent with this
theory of mitigation and does not impeach or diminish the
evidence of his service. To conclude otherwise reflects a
failure to engage with what Porter actually went through
in Korea.
As the two dissenting justices in the Florida Supreme
Court reasoned, “there exists too much mitigating evi
dence that was not presented to now be ignored.” Id., at
937 (Anstead, J., concurring in part and dissenting in
part). Although the burden is on petitioner to show he
was prejudiced by his counsel’s deficiency, the Florida
Supreme Court’s conclusion that Porter failed to meet this
burden was an unreasonable application of our clearly
established law. We do not require a defendant to show
“that counsel’s deficient conduct more likely than not
altered the outcome” of his penalty proceeding, but rather
that he establish “a probability sufficient to undermine
confidence in [that] outcome.” Strickland, 466 U. S., at
693–694. This Porter has done.
The petition for certiorari is granted in part, and the
motion for leave to proceed in forma pauperis is granted.
The judgment of the Court of Appeals is reversed, and the
case is remanded for further proceedings consistent with
this opinion.
It is so ordered.

——————

substance abuse, or psychological problems stemming from service in a

combat theater in the United States military”); Minn. Stat. §609.115,

Subd. 10 (2008) (providing for a special process at sentencing if the

defendant is a veteran and has been diagnosed as having a mental

illness by a qualified psychiatrist).