concurring in the judgment:
Like the majority, I would invalidate the Department of Transportation’s alcohol testing rule. I would do so, however, not on the ground that the agency promulgated the rule on the basis of a mistaken interpretation of the Omnibus Transportation Employee Testing Act of 1991, but rather on the ground that the rule is an impermissible implementation of the plain language of the Act.
In that Act, Congress directed the Department to “establish a program which requires motor carriers to conduct preemployment ... testing of the operators of commercial motor vehicles for use, in violation of law or Federal regulation, of alcohol or a controlled substance.” 49 U.S.C.App. § 2717(a). I believe that, by its plain terms, the Act requires alcohol testing, either before hiring or before work actually begins, for use in violation of law. I find the Act neither “patently] ambigufous]” nor “rife with ambiguity.” See ante at 409-10.1 I believe that the agency understood its directive from Congress precisely as I do. Neither ATA nor the agency contends that the agency construed the Act in the manner suggested by the majority. See ante at 409-10, 411 (ascribing to agency the interpretation that the Act “unambiguously requires pre-hiring alcohol testing of all applicants [for motor carrier positions] without regard for whether a positive test result would indicate use in violation of law.” (emphasis added)). Nor is there any record *415evidence that the agency so interpreted the Act.2
While I believe the Act is plain and the agency regarded it as such, I would nonetheless invalidate the alcohol testing rule because I believe that the rule is, and at the time of its promulgation was likely known by the agency to be, an invalid implementation of Congress’ clear statutory directive. The only interpretations of the statutory term “preemployment” that in my view are defensible, as I note above, reference the period before hiring or the period before the employee actually begins work. The agency’s definition of the term “preemployment,” which includes the period after the employee begins work and up until the employee first undertakes a “safety sensitive” assignment, is irreconcilable with this plain meaning of the term.3 This should be evident, if from nothing else, then from the fact that the statute already covers posthiring “preactivity” testing through its authorization of reasonable suspicion and random’testing. That these tests may also be conducted during or after the particular activity has no relevance to the question of whether Congress has provided for preactivity testing by means of these tests.
The agency’s sophistic argument that the rule is reasonable because the term “preem-ployment” is inherently ambiguous appears to be a post hoc effort to defend a rule that in retrospect appears indefensible, by bringing the authorizing statute within the class of legislative enactments to which Chevron deference must be accorded. The agency nowhere so ' much as hinted that the term “preemployment” might be ambiguous during the promulgation process, as the majority notes. And the authorities that the agency relies upon today for its claim belie any suggestion of perceived ambiguity. The agency can find no better authority for its assertion of ambiguity than a ■ 50-year old case from the California Supreme Court; one federal statute which uses the term “employment,” not “preemployment,” and in which the “activity” meaning ascribed to that term is apparent only from the overall context in which the term appears; and an unspecified number of state workmen’s compensation laws which also use only the term “employment,” but which use it to mean the entire period during which one is in the employ of another, not the “activity” for which the person is hired. See Brief for Respondents at 21-22.
In my view, the agency finds itself in the precarious position it does, either because it mistakenly concluded that preemployment testing only of persons as to whom alcohol consumption would violate federal law would be literally impossible since there are no such persons, or, more likely, because it im-permissibly concluded that the number of persons for whom this might be true would be so small as not to justify the effort that would be required to test them.
If the agency believed that no persons would be reached, by a preemployment test for use in violation of law, it was simply wrong. Any number of federal statutes and regulations proscribe for employees of regulated industries, for government employees, and even for certain non-government employees, the consumption of alcohol at times when those persons might be tested by motor carriers in connection with the preem-ployment process. See, e.g., 49 C.F.R. *416§ 392.5(a) (prohibiting commercial motor vehicle operators from consuming an intoxicating beverage for the four hours before operating a commercial motor vehicle); 10 C.F.R. § 26.20(a) (prohibiting the consumption of alcohol by employees of Nuclear Regulatory Commission licensees “[w]ithin an abstinence period of at least 5 hours preceding any scheduled working tour”); 18 U.S.C. § 3563(b)(8) (“refrain[ing] from excessive, use of alcohol” as a condition of probation); cf. 5 U.S.C. § 7352 (prohibiting habitual use of intoxicating beverages to excess by those employed in the competitive service).4 Thus, contrary to the agency’s belief, it was Congress, not the agency, that was correct in its assumption as to whether persons would be reached by such a test. See, e.g., Brief for Respondents at 20.5
It is more likely, though, that the agency was aware of at least some of these specific proscriptions, but decided that testing for their violation would not be cost-effective. As the majority put it, the agency simply “[took] some liberties with the plain language of the Act for pragmatic ends.” Ante at 411.
While the agency’s representations come perilously close to the disingenuous, see, e.g., Brief for Respondents at 20 (“[T]he statute apparently directs the Secretary to require an impossibility.”), the agency does not actually contend before us that there are no persons who could be tested preemployment for the consumption of alcohol in violation of federal law; rather, it only maintains that preemployment “use of alcohol is typically not in violation of law or Federal regulation,” see id. at 19-20; see also id. at 23 (“‘pre-hiring’ tests would almost never be ‘for violation of law or Federal regulation’ and thus could almost never be done.” (emphasis added)). Moreover, if the agency had believed that it was impossible to administer preem-ployment tests for use in violation of federal law, then presumably it would not have crafted a rule that permits such prehiring testing. The agency’s decision to permit such testing, even though it doubted its usefulness, I take to be a telling admission that the agency recognized that prehiring testing for violations of federal law was possible, and, indeed, that such testing was necessary for the agency not to be in flagrant disregard of the statute Congress enacted.
The agency’s contemporaneous acknowledgment that it promulgated this particular rule in order to make its alcohol testing program “more meaningful,” 59 Fed.Reg. *4177321, likewise makes clear that the agency rejected the testing directed by Congress as less meaningful, if not meaningless, in achieving the purposes underlying the Act. The agency for years has been of the view that preemployment alcohol testing is neither wise policy nor cost-effective. See, e.g., 54 Fed.Reg. 46,337 (1989); 57 Fed.Reg. 59,398 (1992); 59 Fed.Reg. 7321 (1994). Because Congress spoke as clearly as it did in section 2717(a) of the Omnibus Transportation Employee Testing Act, however, the agency was without authority to substitute its long-held view for Congress’ on how best to effectuate the goal of protecting .the public from alcohol and controlled substances abusers, even if the agency’s chosen course would better serve those goals.6
Of course, the court, no less than the agency, is bound by the plain language of congressional enactments. It is for this reason that I cannot agree with the majority’s intimation that any of the various interpretations of the Act it identifies could withstand scrutiny, including the one that we today invalidate. For example, I do not see how the plain language of the Act can be interpreted to require preactivity testing of all applicants. See ante at 411-12. I certainly do not see how the statute can be construed to require “pre-hiring testing of all applicants but only for use of controlled substances.” Id. If nothing else, the statute requires preemployment testing for both controlled substances and alcohol.
I also disagree with the underlying jurisprudential message of the majority opinion that the plain meaning interpretation of the Act, which even the majority acknowledges is “linguistically sound,” ante at 411, might not be sustainable because “it is far from clear how such a reading would really advance the Act’s stated purpose of promoting ‘commercial motor vehicle safety,’ ” id. at 411. When a statute is unambiguous, as this one is, I believe that we have no choice but to order it enforced as written, whether or not in our view it would, as so construed, sufficiently advance the underlying objectives. However tempting is the invitation to weigh the plain language against the overall purposes and legislative history of the Act, id. at 411-12, it is an invitation best declined.
. Not only did Congress plainly require testing of persons for whom alcohol consumption might be illegal before they begin work, it was reasonable for it to have required such testing. Although at the time not necessarily focused on the illegality of the consumption, even the agency has conceded as much. As the Secretary of Transportation acknowledged, preemployment tests "may provide helpful information for use by a medical officer in determining whether an individual has a problem”; they may be "useful as one tool among many for an employer to determine whether an applicant can be expected to perform reliably in a safety-related function”; and they may be used "along with other indicators, as a warning signal about alcohol dependency.” 54 Fed.Reg. 46,326, 46,337 (1989). In fact, because of the virtual certitude that Congress intended such testing for controlled substances, it would seem almost certain that Congress must be understood as having intended such testing for alcohol.
. The preamble to the final rule, the evidence that the majority relies upon for its conclusion, merely states the agency's understanding that “[t]he Act explicitly requires pre-employment testing for covered transportation industiy employees, so we do not have the discretion to eliminate it from these programs.” 59 Fed.Reg. 7321 (emphasis added). This statement says nothing about whether the agency believed the Act required “prehiring" testing or "prehiring” testing of all applicants "without regard for whether” their alcohol use might be in violation of law. It addresses only whether DOT has the discretion not to issue preemployment alcohol testing rules at all, not the timing of any tests that are ultimately administered. For this reason, contrary to the majority's belief, ante at 411, the preamble does not draw into question the agency's present contention that the term "preemployment” is ambiguous.
. That the statute may be read to require testing either before hiring or before the employee begins work does not render the statute ambiguous as it concerns the issue before us, contrary to the majority's contention, see ante at 412 n. 9. The statute is plain in the only sense relevant, namely that it cannot be understood to authorize testing after one begins work.
. See also 49 C.F.R. § 219.101(a) (prohibiting railroad employees from reporting for, or remaining on, duty while under the influence of alcohol); 14 C.F.R. § 91.17 (prohibiting airline crewmembers from working within eight hours after consuming alcohol or while having a blood alcohol concentration of .04 percent or more); 49 C.F.R. § 391.15 (prohibiting commercial motor vehicle operators from driving with a blood alcohol concentration of .04 percent or more); 32 C.F.R. § 552.152(b) (prohibiting alcohol use by military personnel and civilian employees of a particular military institution, while on duty).
Even a cursory review yields countless common-sense, every-day examples of how an individual seeking or awaiting employment as a motor carrier operator could be in violation of the above-cited laws and regulations at a time when the employer could meaningfully conduct a preemployment test for alcohol use in violation of federal law. The majority does not even attempt .to explain or identify those laws or regulations as to which “the literal texts” would not proscribe alcohol consumption at such a time. Ante at 412-13 n. 10.
The majority resorts to mischaracterization of my position in an effort to minimize the class of individuals for whom testing would be required under the plain meaning construction of the Act, so as to avail itself of the so-called " ‘absurd result' canon of statutory interpretation.” Id. Contrary to the majority's assertion, I do not construe the term ‘'preemployment testing" as limited to "prehiring testing.” Id. As I explain, "preemployment" can refer not only to "prehir-ing,” but also to the time after an individual is hired but before he begins work. The majority engages in further mischaracterization when it says that I believe the Act requires testing "of all applicants for illegal alcohol use.” Id. (emphasis added). While testing of all applicants is one way to implement the statutory mandate, the agency is free to devise a more cost-effective alternative that requires less testing, as long as the program satisfies the statutory command.
In sum, it is apparent that the plain terms of the Act yield results that are entirely consistent with a reasonable assessment of congressional intent.
. It follows from the fact that even prehiring testing for illegal alcohol consumption is possible that ATA's argument, that the agency could fore-go prehiring alcohol testing altogether, is similarly flawed, because this argument is premised on the understanding that such testing is impossible.
. It is at least arguable that the agency's rule does not further the purpose of detecting illegal • alcohol use. By permitting testing any time pri- or to the first safety-sensitive assignment, the rule does not target uses that might be in violation of federal law. Except within the several hours immediately before the performance of a safety-sensitive function, drivers generally are not prohibited from consuming alcohol. 49 C.F.R. § 392.5(a). Thus, the agency’s rule at once authorizes testing when consumption would not even be in violation of law and fails to require testing when it might actually detect illegal consumption.