The American Trucking Associations, Inc. ("ATA"), the national trade association of the trucking industry, petitions for review of a final rule issued by the Department of Transportation ("DOT") and the Federal Highway Administration ("FHWA") that mandates preemployment testing of commercial truck drivers for alcohol use. ATA argues that the rule is based on an erroneous interpretation of the governing statute and is therefore not a reasonable exercise of the agencies' interpretive discretion. We agree. Accordingly, we vacate the final rule and remand to the agencies for further rulemaking consistent with this opinion.

The Omnibus Transportation Employee Testing Act of 1991 ("Act" or "1991 Act"), Pub.L. No. 102-143, Title V, 105 Stat. 952 (1991), directed the Secretary of Transportation to prescribe regulations for the testing of employees for drugs and alcohol in four sectors of the transportation industry. The portion of the Act here at issue directs DOT, "in the interest of commercial motor vehicle safety," to

establish a program which requires motor carriers to conduct preemployment, reasonable suspicion, random, and postaccident testing of the operators of commercial motor vehicles for use, in violation of law or Federal regulation, of alcohol or a controlled substance. The Secretary may also issue regulations, as the Secretary considers appropriate in the interest of safety, for the conduct of periodic recurring testing of such operators for such use in violation of law or Federal regulation.

Sec. 5(a)(1), 105 Stat. 959 (codified at 49 U.S.C.App. Sec. 2717(a)). Similar provisions apply to air carriers, railroads, and mass transit authorities as well. Sec. 3(a)(1), 105 Stat. 953; Sec. 4, 105 Stat. 957; Sec. 6(b)(1), 105 Stat. 962.

On December 15, 1992, FHWA and the other operating administrations within DOT1 issued Notices of Proposed Rulemaking ("NPRMs") to implement the Act's mandates. DOT itself issued a common preamble which it explicitly incorporated into each of its administrations' separate NPRMs. 57 Fed.Reg. 59,382 (1992). Because the administrations had previously promulgated drug testing rules,2 the NPRMs and the DOT preamble focused clearly on alcohol testing. Each NPRM proposed that employers would be required to administer pre-employment, reasonable suspicion, post-accident, and random testing for both drugs and alcohol. DOT chose not to require periodic recurring testing.

In its preamble, DOT reiterated views it had expressed three years earlier that pre-employment testing "is one of the least useful types of tests when dealing with alcohol."3 It observed that, because off-duty alcohol use--in contrast to off-duty use of controlled substances--is generally legal, "[o]ften, a test result indicating alcohol use may only indicate bad judgment or bad timing (e.g., one notices an employment advertisement after having beer and a hamburger for lunch, immediately applies, and is tested.)" It also acknowledged that pre-employment testing is especially costly. Nonetheless, DOT tersely observed, "[t]he Act requires pre-employment testing." "To make such a test more meaningful," DOT proposed that "employer[s] would have the option of testing during the hiring process or before (preferably just before) the employee starts performing safety-sensitive functions." 57 Fed.Reg. 59,398.

DOT and its operating administrations received numerous comments critical of the proposal to require pre-employment alcohol testing. As DOT later observed, "[a] substantial number of commentators were concerned about the costs of pre-employment tests and considered them silly 'intelligence' tests and a waste of time." 59 Fed.Reg. 7321 (1994). One comment, submitted jointly by Southwest Airlines and several of its employee associations, directly challenged DOT's assertion that the statute required pre-employment alcohol testing. The comment emphasized that, "under its express terms, the Testing Act requires the [DOT operating administrations] to test for alcohol consumption only when such consumption violates a law or Federal regulation." It continued:

There is no law or Federal regulation, as far as Southwest is aware, which prohibits persons under the influence of alcohol from appearing at an airline to apply for a safety-sensitive job. This being so, under the express terms of the Testing Act, the FAA would appear to be under no legal mandate to prescribe pre-employment testing rules.

J.A. 114 (Joint Comments of Southwest Airlines et al.). ATA also responded to reiterate the ineffectiveness of pre-employment alcohol testing and to contest DOT's expressed belief that all of its administrations were required to prescribe pre-employment alcohol testing. For this latter argument, ATA relied not upon language from the 1991 Act, but rather upon FHWA's pre-existing statutory discretion (unique among DOT's operating administrations) to "waive, in whole or in part, application of any provision of this chapter or any regulation issued under this chapter with respect to [any] class of persons or class of commercial motor vehicles if the Secretary determines that such waiver is not contrary to the public interest." 49 U.S.C.App. Sec. 2711. ATA urged FHWA to exercise its discretion to waive the pre-employment testing provisions of the Act as to "drivers [of commercial motor vehicles] subject to the pre-employment alcohol testing." J.A. 131 (Comments of ATA on Alcohol Use and Testing).

On February 15, 1994, the agencies published a final rule containing both substantive prohibitions on the use of alcohol and testing requirements. The substantive provisions provide, inter alia, that no driver "shall perform safety-sensitive functions [i.e., e.g., waiting to be dispatched, loading, unloading, and driving] within four hours after using alcohol," 59 Fed.Reg. 7507 (to be codified at 49 C.F.R. Sec. 382.207), and that drivers may not have "any measured alcohol concentration" while on duty. 59 Fed.Reg. 7515 (amending 49 C.F.R. Sec. 392.5(a)(2)). The testing provisions retained the requirements for pre-employment testing, in addition to post-accident, reasonable suspicion, and random testing. In its common preamble, DOT largely repeated the remarks regarding pre-employment testing from its earlier NPRM. After noting the criticisms levelled at the rule, DOT stated simply: "The Act explicitly requires pre-employment testing for covered transportation industry employees, so we do not have the discretion to eliminate it from these programs." 59 Fed.Reg. 7321. Yet, DOT continued, in order "[t]o make such a test more meaningful," the final rule would permit employers to administer the "pre-employment" test "any time prior to the first time the employee performs safety-sensitive functions." Id.4

Finally, FHWA rejected ATA's request that it waive application of the Act's pre-employment testing provision to motor carriers:

Even accepting, for the sake of argument, the comment's presumption that pre-employment testing is inherently useless, the FHWA does not believe it has the authority to waive all drivers from a major provision of the legislation. Eliminating all pre-employment tests would greatly diminish the number of required tests, and would, in effect, rewrite the statute.

59 Fed.Reg. 7487.

ATA filed a timely petition for review under the Hobbs Act, 28 U.S.C. Sec. 2342(5), which provides for direct review in the courts of appeals of final rules issued by the Interstate Commerce Commission, read in conjunction with 49 U.S.C.App. Sec. 1653(c), which specifies like review of orders issued pursuant to functions transferred from the ICC to DOT. We have previously acknowledged that exclusive jurisdiction lies in the courts of appeals to review DOT regulations establishing qualifications for motor carrier employees. See Clark v. Skinner, 937 F.2d 123, 126-27 (4th Cir.1991); see also Center for Auto Safety v. Skinner, 936 F.2d 1315 (D.C.Cir.1991) (per curiam); Owner-Operators Indep. Drivers Ass'n v. Skinner, 931 F.2d 582 (9th Cir.1991).

ATA advances two arguments in support of its petition. First, it argues, the agencies erred as a matter of law in construing the Act unambiguously to require them to adopt the regulation that they did. Second, ATA avers, FHWA erred in concluding that it lacked discretion under 49 U.S.C.App. Sec. 2711 to waive the Act's pre-employment testing requirements as to the motor carrier industry. We agree with ATA's first contention and therefore vacate FHWA's final rule insofar as it mandates pre-employment testing for alcohol, and remand to the agencies for further rulemaking. In order to provide greater guidance to the agencies on remand, we also reach ATA's second contention. We uphold as a reasonable construction of the waiver provision FHWA's determination that it lacks discretion to waive a statutory provision as to all motor carrier operators.

The standards that govern our review of an agency's rulemaking are well established. Under Chevron 's familiar two-step analysis, we first ask "whether Congress has directly spoken to the precise question at issue;" if so, we "must give effect to the unambiguously expressed intent of Congress." If the statute is ambiguous, however, we must defer to the agency's interpretation if reasonable or permissible. Chevron USA Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 842-43, 104 S. Ct. 2778, 2781-82, 81 L. Ed. 2d 694 (1984); De Osorio v. United States INS, 10 F.3d 1034, 1037-38 (4th Cir.1993). In this case, there is much disagreement over whether the Act is ambiguous and, if so, wherein the ambiguity lies. Indeed, the agencies themselves have, over time, expressed conflicting views on this question. We conclude that the statute is in fact rife with ambiguity. We vacate the final rule, however, because the interpretation upon which it was based is plainly unreasonable.

The government's present view is that Congress has not provided clear and coherent guidance regarding the necessity and scope of pre-employment alcohol testing. On one hand, the agencies argue, "the Act plainly does require pre-employment testing for illegal alcohol use." Respondents' Brief, at 18. On the other hand, they continue, because "pre-employment use of alcohol is typically not in violation of law or Federal regulation, the statute apparently directs the Secretary to require an impossibility." Id. at 19-20. It seems, in other words, that "Congress assumed that it was possible to do a 'pre-employment' test for use of alcohol 'in violation of law or Federal regulation,' " id. at 20, and that such an assumption was factually mistaken. If so, the agencies could not adopt any interpretation of the Act that would give full effect to congressional intent. Specifically, the agencies could actualize only one of two mandates: that carriers employ pre-employment testing (along with reasonable suspicion, random, and post-accident testing) for both alcohol and controlled substances; or that carriers test only for that use of alcohol or controlled substances which is "in violation of law or Federal regulation." The agencies could realize the latter directive by foregoing pre-employment alcohol testing, or they could realize the former by requiring pre-employment testing notwithstanding that any alcohol use the tests revealed would be lawful.

The agencies contend, however, that they avoided the horns of this dilemma by exploiting a patent ambiguity in the term "pre-employment." Whereas ATA considers " 'pre-employment' ... an unambiguous term, well recognized in the transportation industry and elsewhere, that unambiguously means prior to hiring an applicant for a job," Petitioner's Brief, at 21 n. 15, the government insists that "the term 'employment' is commonly used in two senses--one referring to the legal relationship (the sense petitioner prefers), and the other referring to the actual activity for which someone is hired." Respondents' Brief, at 21. In this latter "activity" sense, "the term 'employment' refers to 'the doing of the work,' plus a reasonable margin to get to and from the place of work." Id. (quoting California Casualty Indem. Exchange v. Industrial Accident Comm'n, 21 Cal. 2d 751, 135 P.2d 158, 161 (1943)). While it is not unlawful to have consumed alcohol prior to applying for a job with a motor carrier, the argument continues, it is unlawful for an employee to "do[ ] the work" (of driving a truck) after having consumed alcohol. Thus, by requiring "pre-employment" testing for alcohol at any time "[p]rior to the first time a driver performs safety-sensitive functions for an employer," 59 Fed.Reg. 7508, the agencies "chose the only interpretation [that] makes sense out of both statutory phrases: 1) 'pre-employment' test, and 2) testing 'for violation of law or Federal regulation.' " Respondents' Brief, at 22. Because such an interpretation, the government concludes, is eminently reasonable, the final rule must be upheld under Chevron deference.

The most obvious problem with this ingenious argument is that the proffered rationale bears little resemblance to the final rule actually promulgated. As DOT explained in its common preamble, the final rule permits employers to conduct the "pre-employment" test "any time prior to the first time the employee performs safety-sensitive functions," including even pre-hiring. 59 Fed.Reg. 7321 (emphasis added). By permitting the pre-employment testing to be conducted pre-hiring (at which point any discovered alcohol use would ordinarily be lawful), the rule does not "require[ ] motor carriers to conduct preemployment ... testing of the operators of commercial motor vehicles for use, in violation of law or Federal regulation, of alcohol." Furthermore, limiting pre-employment testing to "[p]rior to the first time a driver performs safety-sensitive functions," 59 Fed.Reg. 7508 (emphasis added), is not consistent with the activity sense of the word "employment." Whereas the "legal relationship" sense of the word refers to a continuous condition, the "activity" sense refers to a discontinuous one. If "employment" means "the doing of the work," Respondents' Brief, at 21, then during the course of his legal relationship with his employer, an individual operator is repeatedly employed, then unemployed, and employed again. Pursuant to the activity sense of employment, the final rule should require testing "prior to each time a driver performs safety-sensitive functions."

The point is not simply that the agencies stumbled when it came to putting into effect their clever interpretation of the Act. Rather, we believe, the rules themselves belie the agencies' claim that the statutory interpretation they now advance played any part in their actual decisionmaking process. The government points to no evidence in the record which supports the claim that DOT or FHWA ever recognized either of the two ambiguities that drive the government's present argument.5 Indeed, the agencies' contemporaneous remarks suggest the contrary. Most telling is DOT's statement in its preamble to the final rules, that "[t]he Act explicitly requires pre-employment testing for covered transportation industry employees, so we do not have the discretion to eliminate it from these programs." 59 Fed.Reg. 7321; see also 57 Fed.Reg. 59,398 (preamble to NPRMs). The agencies failed utterly to acknowledge the apparent inconsistency arising from the Act's equally explicit requirement that the testing only be "for use, in violation of law or Federal regulation."It is not plausible, moreover, that the agencies had by this time already conceived that "pre-employment" might mean anything other than "pre-hiring." We can reasonably expect that had DOT at that time adopted the unusual "pre-activity" sense of the word it would have said so. DOT's actual explanation that it would permit "pre-employment" testing to be conducted at any time before the first performance of a safety-sensitive function in order to make the rule "more meaningful" indicates instead the agencies' willingness to take some liberties with the plain language of the Act for pragmatic ends. In sum, the record reveals that the agencies read the Act as though it unambiguously requires pre-hiring alcohol testing of all applicants without regard for whether a positive test result would indicate use in violation of law. If the final rule is to withstand even Chevron 's deferential judicial review, it is this actual reasoning that must prove reasonable, not the post hoc rationalization devised during litigation. As the Supreme Court stressed in SEC v. Chenery Corp., the "grounds upon which an administrative order must be judged are those upon which the record discloses that its action was based." 318 U.S. 80, 87, 63 S. Ct. 454, 459, 87 L. Ed. 626 (1943).

As the preceding discussion and the agencies' own arguments during the course of this litigation reveal, however, the interpretation of the Act upon which the agencies actually relied at the rule-making stage is not reasonable. First, if as the agencies themselves now contend, the term "pre-employment" is inherently ambiguous, then the statute did not, as they then believed, unambiguously require pre-hiring testing. Second, for reasons that are somewhat complex, even if, as the agencies then thought, the term did mean "pre-hiring," the statute's ultimate directive remains ambiguous.

The government now argues in its briefs that, if "pre-employment" means "pre-hiring," the statutory language is inherently ambiguous (in the sense of being internally inconsistent). That is, because pre-hiring "use of alcohol is typically not in violation of law or Federal regulation, the statute apparently directs the Secretary to require an impossibility." Respondents' Brief, at 19-20. In fact, though, the conclusion does not follow from the premise. The government's implicit concession that there exists a class of atypical job applicants for whom the use of alcohol at the time of application would be unlawful establishes that the plain language of the Act does not direct the Secretary to require a flat impossibility. Thus, if "pre-employment" means "pre-hiring," the plain language of the Act appears to require only pre-hiring testing of the few job applicants whose use of alcohol at the time of application might be in violation of law6--for example, persons under a state minimum drinking age,7 and persons who apply for employment with a motor carrier even while subject to the alcohol-use regulations of their then-current employment.8 This reading of the statute, though linguistically sound, raises problems of its own. Most conspicuously, it is far from clear how such a reading would really advance the Act's stated purpose of promoting "commercial motor vehicle safety." Therefore, even if "pre-employment" could only reasonably mean "pre-hiring," the overall statutory context and legislative history might provide persuasive grounds to conclude that, despite the force of the Act's plain language, Congress did not really intend to require pre-hiring alcohol testing only of the vanishingly small class of potential applicants as to whom alcohol use is proscribed by a general law. Cf. Public Citizen v. United States Dept. of Justice, 491 U.S. 440, 452-55, 109 S. Ct. 2558, 2565-67, 105 L. Ed. 2d 377 (1989).

For the foregoing reasons, we conclude that the statute is in critical respects ambiguous. Conceivably, it could be construed to require: pre-activity testing of all applicants; pre-hiring testing only of the small subset of applicants as to whom use of alcohol at the time of the test would be "in violation of law or Federal regulation"; prehiring testing of all applicants for use of alcohol and controlled substances; or pre-hiring testing of all applicants but only for use of controlled substances.9 Accordingly, the agencies' actual interpretation--which ignored all the ambiguities that we have identified--is not reasonable. We must, therefore, vacate the final rule.

On remand, the agencies should determine whether, in light of statutory context and purpose, as well as legislative history, "pre-employment" could reasonably mean anything other than "pre-hiring." If the agencies answer that question in the affirmative and interpret the statute to require pre-activity testing for use of alcohol in violation of law or Federal regulation, they should promulgate a regulation that actualizes that meaning. For reasons already discussed, the existing final rule does not do so.

If (as seems to us more likely) the agencies determine that pre-employment means pre-hiring, they must confront the possibility--apparently not recognized by either the agencies or ATA prior to oral argument--that the Act requires pre-hiring testing of the small universe of applicants as to whom use at the time of the test would be in violation of law or Federal regulation. Whether such a plain language construction of the Act is consistent with congressional intent (and does not lead to an absurd result) we leave for first instance determination by the agencies. We expect that in order to reach a conclusion on this matter the agencies will, among other things, determine just how large the relevant set of applicants would be and consider what consequences should attach to a positive test result.10 If the agencies interpret the Act to require pre-hiring testing of persons whose alcohol use at the time of the test would be unlawful, then they must, of course, promulgate an appropriate rule. If the agencies disapprove this interpretation, it would be their task, in the exercise of their reasoned decisionmaking, to privilege one of Congress' apparently inconsistent mandates--that all alcohol testing be conducted only for illegal usage, and that all applicants undergo alcohol testing before being hired--and to promulgate a rule that accords with that interpretation.

As an alternative challenge to the final rule, ATA contends that FHWA erred as a matter of law in concluding that it lacked statutory "authority to waive all drivers from a major provision of the legislation." The Commercial Motor Vehicle Safety Act of 1986 (as amended by the 1991 Omnibus Transportation Employee Testing Act) provides in part:

Notwithstanding any other provision of this chapter ... the Secretary may waive, in whole or in part, application of any provision of this chapter or any regulation issued under this chapter with respect to [any] class of persons or class of commercial motor vehicles if the Secretary determines that such waiver is not contrary to the public interest and does not diminish the safe operation of commercial motor vehicles.

49 U.S.C.App. Sec. 2711.11 In light of the agencies' acknowledged skepticism regarding the utility of pre-employment alcohol testing, ATA's comment below urged FHWA to waive the mandate in accord with its statutory discretion. ATA argues in this petition that, even though FHWA would not have been obligated to exercise its discretion as ATA had requested, the agency erred as a matter of law in construing the waiver provision as not to extend the power upon which ATA would rely. Because we have concluded that the agencies' erroneous interpretation of the 1991 Omnibus Act requires that we vacate the final rule, we need not reach ATA's second contention in order to dispose of this petition. We address it nonetheless so as better to inform the agencies' deliberations on remand.

ATA's objection to FHWA's protestation that it lacks power to waive motor carriers from the Act's requirement of pre-employment alcohol testing (such as it may be) can be simply stated:

The agencies have offered no explanation as to why ... "any provision" and "any regulation" do not encompass this provision and this regulation. The plain language of the statute provides only two prerequisites to the Secretary's exercise of his waiver authority: his determination that a waiver "is not contrary to the public interest" and his determination that a waiver "does not diminish the safe operation of commercial motor vehicles."

Petitioner's Brief, at 26. But this argument misapprehends the agencies' reasoning, which is that "class" denotes something less than the whole, and "waiver" is distinguished from "repeal." "In short," the government explains, "waivers are a device for making sure that a general rule is not applied to special situations in which it makes no sense. Waivers are not a device for deciding that a general rule makes no sense at all and should be scrapped altogether." Respondents' Brief, at 29. The issue, under this view, is not (as ATA would have it) whether the waiver provision extends to this particular statute. Surely it does. Presumably the Secretary could waive application of the pre-employment alcohol testing rule as to, say, motor carriers under a certain size or drivers over a certain age. The question, rather, is whether the agencies enjoy discretion to waive application of the 1991 Act--or of any other legislation--as to the entire universe of the intended objects of the particular statutory provision.

The agencies' contention that they do not reflects a highly defensible interpretation of the waiver provision and is entitled to deference. Commonly understood, administrative "waivers" are a mechanism "to seek out the 'public interest' in particular, individualized cases." WAIT Radio v. F.C.C., 418 F.2d 1153, 1157 (D.C.Cir.1969) (emphasis added). They are not a device for repealing a general statutory directive. Accordingly, we uphold the agencies' determination that 49 U.S.C.App. Sec. 2711 does not authorize them to waive motor carriers from the 1991 Act's pre-employment alcohol testing requirement, however they may construe that requirement on remand.

Because DOT and FHWA misinterpreted the Omnibus Transportation Employee Testing Act of 1991, we vacate the agencies' final rule insofar as it requires alcohol testing of all would-be motor carrier operators prior to their first performance of a safety-sensitive function. We remand for the agencies to reinterpret 47 U.S.C.App. Sec. 2717(a) in the light of this opinion and then to promulgate final rules consistent with that reinterpretation.

VACATED AND REMANDED.

LUTTIG, Circuit Judge, 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. Sec. 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 "patent[ly] ambigu[ous]" 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 evidence 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 "preemployment" 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 impermissibly 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 preemployment process. See, e.g., 49 C.F.R. Sec. 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. Sec. 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. Sec. 3563(b)(8) ("refrain[ing] from excessive use of alcohol" as a condition of probation); cf. 5 U.S.C. Sec. 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 preemployment 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. 7321, 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.