concurring:
I fully concur in the majority opinion, and write separately only to state that I find perplexing the dissent’s purported reliance on Chevron USA, Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984). Taken to its logical extreme, the dissent’s position turns Chevron on its head, into a doctrine without limits. But Chevron■ is limited: it applies only when an agency is exercising its delegated authority. See Natural Resources Defense Council v. Reilly, 983 F.2d 259, 266 (D.C.Cir.1993) (“[I]t is only legislative intent to delegate such authority that entitles an agency to advance its own statutory construction for review under the deferential second prong of Chevron.”) (Edwards, J., joined by R.B. Ginsburg and Williams, JJ.) (quoting Kansas City v. Department of Housing & Urban Dev., 923 F.2d 188, 191-92 (D.C.Cir.1991)).
In this case, Congress established an explicit scheme for the initiation of representation proceedings before the National Mediation Board (“NMB”), and under that scheme, the NMB has absolutely no delegated authority to initiate a proceeding on its own or on the request of a carrier, or to promulgate rules to achieve these results. The NMB cannot now claim that authority in the name of convenience, any more than *142the National Labor Relations Board (“NLRB”) can claim such authority under the National Labor Relations Act. See 29 U.S.C. § 159 (1988) (nowhere indicating that the NLRB has authority to pursue, on its own initiative, questions of employee representation). The absence of “thou shalt not” language is irrelevant, for both the Railway Labor Act and the National Labor Relations Act make it clear that only parties other than the NMB and NLRB are authorized to invoke representation proceedings.
Moreover, the mere existence of an agency does not give it the power to assert authority that Congress has not delegated. It is absurd to suggest that, under the second prong of Chevron, there is a statutory “gap to fill” or a statutory “ambiguity” to cure whenever a statute fails to specify some authority that an agency seeks to invoke. This cannot be the meaning of Chevron, for it would allow federal agencies to claim limitless authority except in those few circumstances where Congress has expressly said “thou shalt not” exercise such authority. If we were to allow the NMB to assume the authority it has claimed for itself in this case, we would effectively invite it to assert any power over employee relations in the railroad and airline industries without regard to the statutory limitations prescribed by Congress. Such a decision would make no sense, and it surely would not comport with the mandate of Chevron. As the Supreme Court itself made clear in Chevron: “The judiciary is the fipal authority on issues of statutory construction and must reject administrative constructions which are contrary to clear congressional intent.” 467 U.S. at 843 n. 9, 104 S.Ct. at 2782 n. 9.