Opinion for the Court filed by Circuit Judge EDWARDS.
Concurring opinion filed by Circuit Judge RANDOLPH.
Dissenting opinion filed by Circuit Judge STEPHEN F. WILLIAMS.
HARRY T. EDWARDS, Circuit Judge:Under Section 2, Ninth of the Railway Labor Act (“RLA” or “Act”), the National Mediation Board (“NMB” or “Board”) is given very limited authority to investigate representation disputes “among a carrier’s employees.” See 45 U.S.C. § 152 Ninth (1988). Such investigation is initiated only “upon request of either party to the dispute,” and it is clear that a carrier is not a “party” under Section 2, Ninth. Id. Following investigation, the Board certifies “to both parties,” and “to the carrier,” the employees’ designated bargaining agent. Id. Nothing in this statutory provision authorizes the Board to investigate or resolve a representation dispute either sua sponte or pursuant to a petition from a carrier; and for more than fifty years following the enactment of the RLA, the Board acted to address representation disputes only when it received requests from or on behalf of employees.
Despite the absence of any statutory authority, the Board announced in 1989 that carriers, as well as the Board itself, could initiate representation proceedings in the wake of railroad mergers and acquisitions, on the theory that such events were likely to precipitate uncertainty as to the proper representation of employees. See Procedures for Handling Representation Issues Resulting from Mergers, Acquisitions or Consolidations in the Railroad Industry, 17 N.M.B. 44 (1989) (“Merger Procedures”). Appellants, a coalition of unions representing railroad employees, challenged the Merger Procedures as an illegal arrogation of authority not conferred by the Act. The District Court dismissed appellants’ suit as unreviewable under Switchmen’s Union of North America *659v. NMB, 320 U.S. 297, 64 S.Ct. 95, 88 L.Ed. 61 (1943). On appeal, in an opinion by then-judge Ruth B. Ginsburg, a divided panel of this court reversed, holding that judicial review was available and that the Board had exceeded its statutory authority. See Railway Labor Executives’ Ass’n v. NMB, 988 F.2d 133 (D.C.Cir.1993). Having accepted the Board’s suggestion for rehearing en banc, we again reverse.
The Supreme Court has made clear both that the Board’s authority under Section 2, Ninth is “exclusive” only “[iff the present dispute falls within § 2, Ninth,” General Comm. of Adjustment v. Missouri-Kan.-Tex. R.R., 320 U.S. 323, 336, 64 S.Ct. 146, 152, 88 L.Ed. 76 (1943) (emphasis added), and that the Board’s role under Section 2, Ninth is very narrow. See Switchmen’s, 320 U.S. at 304, 305, 64 S.Ct. at 98, 99, 88 L.Ed. 61. The Board does not even claim that the terms of Section 2, Ninth support the authority that it asserts, and it can point to no other provision in the RLA giving it the authority to promulgate the Merger Procedures. Instead, the Board would have us presume a delegation of power from Congress absent an express withholding of such power. This comes close to saying that the Board has the power to do whatever it pleases merely by virtue of its existence, a suggestion that we view to be incredible. Because we find that the Board’s attempt to expand its jurisdiction has no basis whatsoever in the language of the statute or its legislative history, and because the Board’s novel claim of authority is belied by longstanding agency practice, we hold that the Merger Procedures constitute a “gross violation” of Section 2, Ninth.1
Judicial review is available because the challenged action constitutes a “gross violation” of the Act. Having found such a violation, it is clear that appellants must prevail on the merits. Accordingly, we reverse the judgment of the District Court dismissing appellants’ complaint; we remand case number 91-5223 for entry of declaratory and injunctive relief in appellants’ favor; and we remand case number 91-5310 for reconsideration in light of the new judgment in case number 91-5223.
I. BACKGROUND
Enacted in 1926, the RLA is a comprehensive statute governing labor relations in the railroad and airline industries. In 1934, Congress amended the Act to create the National Mediation Board, a three-member agency whose primary function is to mediate labor disputes among employees and carriers covered by the RLA. See 45 U.S.C. § 154 (1988). Section 2, Ninth of the Act also endows the Board with limited jurisdiction to investigate representation disputes among employees “upon request of either party to the dispute,” and, following such investigation, to certify to the parties and to the carrier the identity of the designated bargaining representative. Id. at § 152 Ninth.
For more than fifty years following its creation, the Board unvaryingly conducted representation investigations only at the behest of employees or their representatives. In 1987, however, with no direction from Congress, the Board decided that existing procedures under Section 2, Ninth were “inadequate to provide for a fair and orderly resolution of representation matters put into flux by a merger.” Trans World Airlines/Ozark Airlines, 14 N.M.B. 218, 241 (1987). The Board announced its intention to promulgate revised procedures with prospective application for handling representation disputes sparked by mergers, acquisitions and consolidations, and it set forth immediately effective interim procedures which permitted carriers to invoke the Board’s jurisdiction in those eases. See id. at 241-42; see also Missouri Pacific Railroad (Union Pacific), 15 N.M.B. 95, 111 (1988) (clarifying that Trans World Airlines/Ozark Airlines “interim procedures were meant to apply to the railroad industry as well as the airline industry”). Thereafter, the Board sought comment from carriers and labor organizations on a draft of the Merger Procedures, *660and, in November 1989, issued them in final form.
The Board purported to rest promulgation of the Merger Procedures on “established authority under Section 2, Ninth, of the Railway Labor Act.” 17 N.M.B. at 44. The Board cited no specific language in the statute to support this assertion. Rather, recognizing that mergers2 may lead to changes in craft or class designations and may result in multiple certifications for the same craft or class of employees, the NMB concluded that expanded investigatory procedures were appropriate in order to further the Board’s purported mandate of certifying only unions which represent the “majority of a system-wide class of employees.” See id. at 46. Accordingly, the Merger Procedures seek to require carriers to inform the NMB in writing of intent to merge, after which the Board will conduct an investigation to resolve “the status of the certifications on the merged carrier.” Id. at 51.
The Merger Procedures also contemplate that the Board sua sponte may investigate the status of post-merger certifications. Thus, for example, the Procedures state that it is “the affirmative responsibility of the Board” under the Act to determine the status of its prior certifications. Id. at 47; see also id. at 49 (asserting that the Board retains “flexibility to appropriately investigate and apply its procedures to different situations which may arise in the future”). Moreover, at no time in this litigation has the Board disavowed the appellants’ claim that the Procedures seek to empower the Board to investigate a carrier’s representation status on its own initiative.
Following the issuance of the Merger Procedures, the Railway Labor Executives’ Association and eighteen other rail labor unions (collectively, “RLEA”) filed this suit in the District Court. RLEA sought both a declaratory judgment that the Board lacked statutory authority to promulgate the Merger Procedures and a permanent injunction against their enforcement. The District Court, relying on Switchmen’s, dismissed RLEA’s complaint on the ground that the adoption of the Merger Procedures fell “within the unreviewable discretion of the NMB.” Railway Labor Executives’ Ass’n v. NMB, No. 89-3306, at 7, 1991 WL 420181 (D.D.C. June 10, 1991) (memorandum opinion).3 A panel majority of this court reversed, concluding that Section 2, Ninth “does not bear the new construction the Board has placed upon it.” Railway Labor Executives’ Ass’n v. NMB, 988 F.2d at 134. The panel majority held that judicial review was not foreclosed by Switchmen’s or Leedom v. Kyne, 358 U.S. 184, 79 S.Ct. 180, 3 L’.Ed.2d 210 (1958), because the Merger Procedures constituted a wrongful arrogation of power by the Board in “gross violation” of the RLA. 988 F.2d at 134. The full court thereafter granted the Board’s suggestion for rehearing en banc.
On appeal, RLEA argues that the plain text and legislative history of Section 2, Ninth compel the conclusion that the Board may not investigate a representation dispute except upon request of the employees involved in the dispute. Because the Merger Procedures seek to authorize representation proceedings at the initiation of the Board or carriers, RLEA contends that the Procedures represent a gross violation of the RLA which may be reviewed by this court. In defense, the Board claims, first, that under Switchmen’s, this court is powerless to review the Merger Procedures, and, second, *661that the Merger Procedures are a permissible interpretation of Section 2, Ninth to which this court owes deference. The Board’s support for the latter argument consists largely of the contention that because Section 2, Ninth does not expressly bar the agency from investigating representation disputes in circumstances other than those enumerated, the Board is free to do so. As we explain, our reading of the text and legislative history of Section 2, Ninth accords with that of appellants, and we therefore reverse the judgment of the District Court.
II. Analysis
A Reviewability of Board Actions Under Section 2, Ninth
1. The General Legal Framework
In Texas & New Orleans Railroad Co. v. Brotherhood of Railway & Steamship Clerks, 281 U.S. 548, 50 S.Ct. 427, 74 L.Ed. 1034 (1930), and Virginian Railway Co. v. System Federation No. 40, 300 U.S. 515, 57 S.Ct. 592, 81 L.Ed. 789 (1937), the Supreme Court established that if the absence of jurisdiction of the federal courts would result in a sacrifice or obliteration of a right that Congress created under the RLA, there would be a compelling inference that the general jurisdiction of the federal courts provides a basis for review. See also Switchmen’s, 320 U.S. at 300, 64 S.Ct. at 96-97. Thus, when a statutory command is “explicit and unequivocal,” or when Congress has “codifi[ed] ... rules governing ... controversies” or stated “the various principles of agency which were to govern the solution of disputes” under Section 2, Ninth, the federal courts have jurisdiction to enforce the congressional command. General Comm. of Adjustment, 320 U.S. at 335, 64 S.Ct. at 151-52.
The Supreme Court was concerned, however, that if general federal jurisdiction were left fully open, the federal courts might unduly interfere with the work of the Board in routine cases involving a mere “application of the principles of collective bargaining and majority rule.” Id. at 334, 64 S.Ct. at 151. Thus, in Switchmen’s, the Court held that the Board’s certification of representatives pursuant to Section 2, Ninth was a function committed exclusively to the NMB and was not judicially reviewable. The Board’s role was to “find the fact [of representation] and then cease,” and the Court found “plain” congressional intent that “the dispute was to reach its last terminal point when the administrative finding was made. There was to be no dragging out of the controversy into other tribunals of law.” Switchmen’s, 320 U.S. at 305, 64 S.Ct. at 99.
Switchmen’s has not been taken to mean, however, that all Board actions which fall within Section 2, Ninth’s compass are immunized from judicial review. To the contrary, in accordance with the principles enunciated in Leedom v. Kyne, which relied in part on Switchmen’s, federal courts have jurisdiction to review “action[s] taken in excess of delegated powers.” Leedom v. Kyne, 358 U.S. at 190, 79 S.Ct. at 184. In Leedom v. Kyne, the Supreme Court held that the district court had jurisdiction to set aside a certification of the National Labor Relations Board (“NLRB”) where that agency had refused to poll professional employees before combining them in a bargaining unit with non-professional employees. Rejecting the NLRB’s claim that the National Labor Relations Act (“NLRA”) foreclosed review, the Court found jurisdiction to review because the NLRB had acted “in excess of its delegated powers and contrary to a specific prohibition in the [NLRA].” Id. at 188, 79 S.Ct. at 184. Section 9(b)(1) of that statute, which provides that the NLRB “shall not” certify a bargaining unit comprising both professional and non-professional employees “unless a majority of such professional employees vote for inclusion” in the unit, id. at 185, 79 S.Ct. at 182 (quoting NLRA), was “clear and mandatory,” and its violation was subject to judicial review. Id. at 188, 79 S.Ct. at 184. The Court said that it “cannot lightly infer that Congress does not intend judicial protection of rights it confers against agency action taken in excess of delegated powers.” Id. at 190, 79 S.Ct. at 184.
Although Leedom v. Kyne itself dealt with a “shall not” statutory command, its application is not so narrowly limited. As we reasoned in Miami Newspaper Printing Pressmen’s Union Local 46 v. McCulloch, *662322 F.2d 993, 997 (D.C.Cir.1963) (McGowan, J.), an agency (in that case, the NLRB) could as well exceed its delegated powers by failing to adhere to a specific affirmative command. Thus, we were “unable to read the Court’s decision in Leedom v. Kyne as limited to the negatively worded prohibition there involved.” See id. The Supreme Court implicitly approved this reasoning in Brotherhood of Railway & Steamship Clerks v. Association for the Benefit of Non-Contract Employees, 380 U.S. 650, 661, 85 S.Ct. 1192, 1198, 14 L.Ed.2d 133 (1965) [“Railway Clerks”], which held that NMB action was reviewable to the extent of insuring that the Board had complied with its affirmative statutory duty to investigate representation disputes. See also Physicians Nat’l House Staff Ass’n v. Fanning, 642 F.2d 492, 496 (D.C.Cir.1980) (en banc) (agency must violate a specific command), cert, denied, 450 U.S. 917, 101 S.Ct. 1360, 67 L.Ed.2d 342 (1981). Thus, it is of no moment that Section 2, Ninth does not state that “the Board shall not conduct an investigation except on the request of an employee,” so long as we may conclude (as we do) that Section 2, Ninth imposes a clear and mandatory obligation upon the NMB to investigate representation disputes only at the behest of the affected employees. We reject any suggestion in our prior cases that it remains open to question whether Leedom v. Kyne applies only to negative commands.
In establishing a framework for review pursuant to Switchmen’s and Leedom v. Kyne, recent decisions of the circuit have suggested that “[jjudicial review of NMB decisions is one of the narrowest known to the law,” and have held that the “courts have no authority to review NMB certification decisions in the absence of ... a gross violation of the Railway Labor Act.” International Ass’n of Machinists v. Trans World Airlines, Inc., 839 F.2d 809, 811 (D.C.Cir.1988), cert. denied, 488 U.S. 820, 109 S.Ct. 62, 102 L.Ed.2d 40 (1988); see also Professional Cabin Crew Ass’n v. NMB, 872 F.2d 456, 459 (D.C.Cir.), cert. denied, 493 U.S. 974, 110 S.Ct. 497, 107 L.Ed.2d 500 (1989) (same effect). But these decisions have been premised, as was Switchmen’s, on the assumption that the action of the Board fell within the compass of authority delimited by Section 2, Ninth. That is not the case here, for not only do the Merger Procedures constitute a “gross violation” of the Act, but the Board has no threshold jurisdiction to act at all in the absence of a request from the employees involved in a representation dispute.
Thus, our prior cases do not tell the whole story. The nonreviewability rule announced in Switchmen’s always must be understood in light of the very circumscribed role the Board was thought to play under Section 2, Ninth. As the Supreme Court explained:
The Mediation Board makes no ‘order.’ And its only ultimate finding of fact is the certificate. The function of the Board under § 2, Ninth is more the function of a referee. To this decision of the referee Congress has added a command enforcible by judicial decree. But the ‘command’ is that ‘of the statute, not of the Board.’
Id., 320 U.S. at 304, 64 S.Ct. at 98 (citations omitted; emphasis added). The Court continued:
Under this Act Congress did not give the Board discretion to take or withhold action, to grant or deny relief. It gave it no enforcement functions. It was to find the fact and then cease. Congress prescribed the command.
Id. at 305, 64 S.Ct. at 99. These passages demonstrate that the Board has no freewheeling authority to act as it sees fit with respect to anything denoted a “representation dispute.” The Board’s authority is exclusive only with respect to the precise matters delimited by Section 2, Ninth. If employees have not sought an “investigation” under Section 2, Ninth, none can be initiated because the statute limits action to cases initiated by “employees.”
Switchmen’s itself—the very case on which the Board relies so heavily for its claim that we lack authority to review the Merger Procedures—thus makes abundantly clear that the Supreme Court crafted a very sweeping rule for a very limited class of cases: While the Board enjoys exceptional latitude when acting within its proper sphere of Section 2, Ninth power, that sphere itself is exceptionally narrow. Viewing Switchmen’s in this *663light, it is difficult to conclude that the Supreme Court intended to insulate from review every action of the Board which arguably involves a question of representation, including those (like the one at bar) that bear absolutely no relationship to “find[ing] the fact” of who employees desire as their representative.4 Switchmen’s, 320 U.S. at 305, 64 S.Ct. at 99; accord America West Airlines, Inc. v. NMB, 986 F.2d 1252, 1256 (9th Cir.1992) (as amended Feb. 26, 1993). In this ease, the Merger Procedures present a question of the Board’s very jurisdiction — a question that is analytically distinct from and antecedent to the issue of whether the Board has correctly found the “fact” of representation. And as the Supreme Court emphasized, “the administrative remedy is exclusive” only “[i]f the present dispute falls within § 2, Ninth.” General Comm, of Adjustment, 320 U.S. at 336, 64 S.Ct. at 152 (emphasis added).
2. The Special Case of Jurisdictional Questions
As we explain below, we have no doubt that the Merger Procedures constitute a bald and insupportable arrogation of power not conferred by the RLA; as such, the Procedures are reviewable under the traditional Leedom v. Kyne analysis. We pause here, however, to note another theory, urged by appellants, under which the Merger Procedures might be amenable to judicial review.
As we have observed in a prior decision, this circuit’s law on the reviewability of NMB orders has developed along two tracks. See International Longshoremen’s Ass’n v. NMB, 785 F.2d 1098, 1099-1100 (D.C.Cir.1986) (summarizing development of dual lines of authority). The first track holds that Board certification orders ordinarily are un-reviewable, unless they fall within the ambit of Leedom v. Kyne. The second track, which had its genesis in two pre-Leedom v. Kyne decisions from the 1950s, holds that the court may review orders in which the Board con-eludes that it lacks jurisdiction to resolve a representation dispute. See American Air Export & Import Co. v. O’Neill, 221 F.2d 829 (D.C.Cir.1954); Air Line Dispatchers Ass’n v. NMB, 189 F.2d 685 (D.C.Cir.), cert. denied, 342 U.S. 849, 72 S.Ct, 77, 96 L.Ed. 641 (1951) [“ALDA”].
Appellants urge us to abolish this distinction and to adopt a rule that all matters involving the Board’s jurisdiction, not merely refusals of jurisdiction, are reviewable. They point out that those circuits which have squarely confronted the issue have held that threshold questions implicating the Board’s jurisdiction to act under Section 2, Ninth fall outside Switchmen’s proscription against review. See Delpro Co. v. Brotherhood Ry. Carmen, 676 F.2d 960, 962 (3d Cir.) (“judicial review of NMB decisions concerning its own jurisdictional authority is not barred”), cert. denied 459 U.S. 989, 103 S.Ct. 343, 74 L.Ed.2d 384 (1982); International Longshoremen’s Ass’n v. North Carolina Ports Auth., 463 F.2d 1, 3 (4th Cir.) (issue in Switchmen’s “was not one of jurisdiction, but of the validity of a Board ruling on a substantial subject clearly within its authorized field”), cert. denied, 409 U.S. 982, 93 S.Ct. 318, 34 L.Ed.2d 245 (1972); see also United States v. Feaster, 410 F.2d 1354, 1361-62 (5th Cir.) (suggesting that judicial review of jurisdictional question might be available, but finding issue not ripe), cert. denied, 396 U.S. 962, 90 S.Ct. 427, 24 L.Ed.2d 426 (1969). Each of these cases involved the question whether a particular employer was a “carrier” within the meaning of the Act and thus subject to the Board’s jurisdiction.
Although we need not resolve this issue conclusively in light of our holding that the Merger Procedures are reviewable under Leedom v. Kyne, on reexamination we find it difficult to support the distinction drawn in our prior cases between Board decisions asserting statutory jurisdiction and those declining to exercise it. Indeed, in endorsing a *664distinction, ALDA noted that in Switchmen’s and its two companion cases, “[t]he question was not as to the power of the Board to resolve the dispute but whether it had done so in an erroneous manner.” ALDA, 189 F.2d at 687-88. Under this interpretation of Switchmen’s, appellants’ challenge to the Merger Procedures, which is based not on the substance of any Board certification but on the issue of whether the Board has threshold authority, or jurisdiction, to act in the absence of a request from the employees involved in a representation dispute, could logically be reviewable as well.
Although ALDA apparently considered Switchmen’s and its companions to have reserved only the question whether a refusal to exercise jurisdiction was reviewable, see 189 F.2d at 688, we do not think Switchmen’s must be read so narrowly. An assertion of jurisdiction based on the erroneous belief that authority exists does not materially differ from a refusal to exercise jurisdiction based on the erroneous conclusion that statutory authority is lacking, and Switchmen’s may not preclude review of either determination. On this point, the Fifth Circuit has noted that “it might be said that while Switchmen’s Union holds that there is no judicial review where the Board has exercised its informed discretion” on a matter related to finding the fact of representation, Switchmen’s “does not preclude judicial review of questions of law which bear directly upon the jurisdiction of the Mediation Board.” Feaster, 410 F.2d at 1361.
We are cognizant that it may not always be a simple task to distinguish between Board actions which implicate the Board’s threshold jurisdiction and those which are simply an erroneous exercise of functions legitimately entrusted to the Board’s discretion under Section 2, Ninth (and, therefore, are reviewable only under the auspices of Leedom v. Kyne ).5 Inventive or mischievous litigants no doubt would find ways to characterize as “jurisdictional” a broad range of Board actions, even those that no one reasonably would doubt to be within the compass of the Board’s authority under Section 2, Ninth. Because we do not wish to extend such an invitation unnecessarily, we rest on our holding that this case is reviewable under the traditional Leedom v. Kyne analysis and leave for another day a fuller reconciliation of the jurisdiction-exercising versus jurisdiction-declining dichotomy set up in ALDA
B. Analysis of Section 2, Ninth
The Board does not deny that the Merger Procedures seek to allow both the Board and carriers to initiate representation proceedings under Section 2, Ninth. Nor does the Board deny that in this respect the Merger Procedures are directly at odds with more than fifty years of unbroken practice under Section 2, Ninth. We need look no further than the language of Section 2, Ninth, the structure of the Act, and its legislative history to determine that these proposed procedures are not only unprecedented, but legally insupportable as well. In its defense of the Merger Procedures, the Board offers little more than the argument that we should defer to its construction of Section 2, Ninth. Yet, the Board cannot point to any statutory text or legislative history to support its position. And our analysis leads us to the firm conclusion that Congress left no ambiguity in Section 2, Ninth: the Board may investigate a representation dispute only upon request of the employees involved in the dispute. For the Board to act otherwise is for the Board blatantly to exceed its statutory authority.
1. The Plain Language
Section 2, Ninth of the RLA provides:
*665If any dispute shall arise among a carrier’s employees as to who are the representatives of such employees designated and authorized in accordance with the requirements of this chapter, it shall be the duty of the Mediation Board, upon request of either party to the dispute, to investigate such dispute and to certify to both parties, in writing, within thirty days after the receipt of the invocation of its services, the name or names of the individuals or organizations that have been designated and authorized to represent the employees involved in the dispute, and certify the same to the carrier. Upon receipt of such certification the carrier shall treat with the representative so certified as the representative of the craft or class for the purposes of this chapter. In such an investigation, the Mediation Board shall be authorized to take a secret ballot of the employees involved, or to utilize any other appropriate method of ascertaining the names of their duly designated and authorized representatives in such manner as shall insure the choice of representatives by the employees without interference, influence, or coercion exercised by the carrier. In the conduct of any election for the purposes herein indicated the Board shall designate who may participate in the election and establish the rules to govern the election, or may appoint a committee of three neutral persons who after hearing shall within ten days designate the employees who may participate in the election. The Board shall have access to and have power to make copies of the books and records of the carriers to obtain and utilize such information as may be deemed necessary by it to carry out the purposes and provisions of this paragraph.
45 U.S.C. § 152 Ninth (emphasis added).
The above language makes perfectly clear that, as used in Section 2, Ninth, the term “parties” includes neither carriers nor the Board itself. Indeed, the Board does not claim otherwise. Because the requisite “dispute” must arise “among a carrier’s employees,” per the first clause of Section 2, Ninth, the succeeding phrase “upon request of the parties to the dispute” can refer only to those same employees. If Congress had considered carriers to be embraced within “parties to the dispute,” the final clause of the first sentence would be entirely superfluous. There would be no need to command the Board to certify the results of the investigation “to both parties” and also to “certify the same to the carrier.” See Reiter v. Sonotone Corp., 442 U.S. 330, 339, 99 S.Ct. 2326, 2331, 60 L.Ed.2d 931 (1979) (court’s duty in construing statute is “to give effect, if possible, to every word Congress used”); United States v. McGoff, 831 F.2d 1071, 1080 (D.C.Cir.1987) (same).
Furthermore, the entire structure of Section 2, Ninth makes it plain that representation investigations and elections are conducted only at the behest and for the specific protection of “employees.” The “duty of the Mediation Board” to “investigate” does not arise except “upon request of either party,” i.e., “employees.” The Mediation Board is only “authorized” to conduct an election in connection with “such an investigation” as is prescribed by Section 2, Ninth. When authorized to act, the Board is instructed to “insure the choice of representatives by the employees without interference, influence, or coercion exercised by the carrier.” An “election” can be conducted only “for the purposes herein indicated,” i.e., to resolve a dispute “among a carrier’s employees” “upon request of either party to the dispute.” And the Board is even given the power to gain access “to the books and records of the carriers,” but only to “carry out the purposes and provisions” of Section 2, Ninth.
In short, when read with care, it is apparent that, in enacting Section 2, Ninth, Congress was quite precise in defining what it meant by “[disputes as to [the] identity of representatives” — the title of Section 2, Ninth — and in codifying rules governing the resolution of such disputes. As the Supreme Court has made clear, such “command[s]” are “enforcible by judicial decree.” General Comm. of Adjustment, 320 U.S. at 335, 64 S.Ct. at 152.
Reference to other sections of the RLA confirms that Section 2, Ninth does not contemplate action-initiating roles either for the Board or for carriers. Thus, where Congress intended carriers and employees to be *666treated alike (that is, like “parties”) with respect to the resolution of particular disputes, this is made plain in the statute. Section 2, Sixth, for example, provides that “[i]n case of a dispute between a carrier or carriers and its or their employees, arising out of grievances ... it shall be the duty of the designated representative or representatives of such carrier or carriers and of such employees ... to specify a time and place at which [a conference] shall be held_” 45 U.S.C. § 152 Sixth (1988). Similarly, Section 2, Second provides that “[a]ll disputes between a carrier or carriers and its or their employees shall be considered ... in conference between representatives designated” by the carrier and employees. 45 U.S.C. § 152 Second (1988). These sections go far to negate any argument that the term “parties” in Section 2, Ninth should be read to encompass anyone other than the employees mentioned in the first clause of that section.6
It is also clear that where Congress meant to endow carriers with the right to invoke the Board’s jurisdiction, or to authorize the Board to offer its services, it did so explicitly. Thus, Section 5, First provides that “[t]he parties, or either party, to a dispute between an employee or group of employees and a carrier may invoke the services of the Mediation Board in any of the following cases ...,” 45 U.S.C. § 155 First (1988), and proceeds to state clearly the circumstances under which the Board’s mediation services may be had. Section 5, First also explicitly empowers the Board to assert its jurisdiction sua sponte, providing that “The Mediation Board may proffer its services in case any labor emergency is found by it to exist at any time.” Id.
The fact that Congress omitted equivalent language in Section 2, Ninth cannot be deemed unintentional or immaterial. Thus, for instance, in Landers v. National Railrood Passenger Corp., 485 U.S. 652, 108 S.Ct. 1440, 99 L.Ed.2d 745 (1988), the Supreme Court said: “That Congress [in the RLA] expressly provided railroad employees with the right to the representative of their choice in Adjustment Board proceedings, but did not do so with regard to any earlier phase of the dispute resolution process, is persuasive evidence ” that such a right does not exist at earlier phases. Id. at 656, 108 S.Ct. at 1442 (emphasis added). See also id. at 657, 108 S.Ct. at 1443 (finding “no merit” in contention that right to be represented by minority union “is implicit” in Section 2, Eleventh (c)); INS v. Cardoza-Fonseca, 480 U.S. 421, 432, 107 S.Ct. 1207, 1213, 94 L.Ed.2d 434 (1987) (“[W]here Congress includes particular language in one section of a statute but omits it in another section of the same Act, it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion.”) (quoting Russello v. United States, 464 U.S. 16, 23,104 S.Ct. 296, 300, 78 L.Ed.2d 17 (1983)). The inescapable conclusion from the plain language of Section 2, Ninth, therefore, is that Congress intended neither carriers nor the Board to initiate representation proceedings.
The crux of the Board’s claim in this ease is that as Section 2, Ninth does not expressly forbid the Board from asserting jurisdiction over a representation dispute in circumstances other than upon employee request, it should not be prohibited from doing so. But the language of Section 2, Ninth does not admit of this argument. The subordinate clause “upon request of the parties” expresses a limiting condition. Indeed, the entire first sentence of Section 2, Ninth imposes strict limitations on the Board’s power. The sentence imposes four significant conditions that must be satisfied as a prelude to the Board’s authority to investigate a representation dispute: there must be a dispute; the dispute must relate to representation; it *667must be among a carrier’s employees; and one of the parties to the dispute must request the Board’s services in resolving it. See 45 U.S.C. § 152 Ninth. Congress effectively has provided a “who, what, when, and how” laundry list governing the Board’s authority. These limitations are utterly inconsistent with the notion that the Board blithely may decide that certain circumstances present such an inherent risk of a representation dispute that the Board may investigate at will.
Indeed, as established at oral argument, a finding that the Board may investigate representation disputes sua sponte would have far-reaching implications. Under such a regime, it would make no difference who brought an alleged dispute to the Board’s attention — a rail passenger worried about service interruptions in the wake of a merger could write to the Board suggesting that it investigate, even where the merger in fact had created no representation issues (as might be the case if, for example, the same national union represented employees on both the merged and acquiring carriers). Furthermore, the Board’s power to meddle in railway labor relations would not be limited to the merger context. The Board could just as well announce, for example, that internal union elections and change of leadership automatically warrant Section 2, Ninth investigations because those events create a possibility of employee dissatisfaction with their certified representative. Yet, the notion that the Board enjoys this sort of power is plainly belied by the tightly confined role Congress assigned to the Board under Section 2, Ninth.
2. Legislative History
When Congress took up the RLA amendments in May 1934, it had before it two versions of what is now Section 2, Ninth from which to choose. The House considered H.R. 7650, a bill prepared by rail labor and introduced by Representative Crosser, alongside H.R. 9689, a similar bill prepared by federal Commissioner of Transportation Joseph B. Eastman and introduced by Representative Rayburn. See Railway Labor Act Amendments: Hearings on H.R. 7650 Before the House Comm, on Interstate and Foreign Commerce, 73d Cong., 2d Sess. 1 (1934) [“H.R. 7650 Hearings ”]. The version that Congress rejected specifically treated carriers as a “party” to representation disputes, and thus would have left no question as to the right of carriers to invoke the Board’s jurisdiction. The rejected language provided:
If any dispute shall arise between a carrier and a group of its employees as to who are the representatives of such employees designated and authorized in accordance with the requirements of the third paragraph of this section, it shall be the duty of the Board of Mediation, upon request of either party to the dispute, to investigate such dispute and to certify to both parties, in writing, [the identity of the designated representatives].
H.R. 7650, 73d Cong., 2d Sess. (1934) (Section 2, Eighth), reprinted in 1 The Railway Labok Act of 1926, A Legislative History, at 775 (ABA 1988) [hereinafter 1 Railway Labor Aot].7 Congress’ refusal to enact language which would have established unequivocally the carriers’ right to invoke the Board’s jurisdiction is strong evidence that Congress did not intend the Board to have the power to confer that right on its own. Cf. Landers, 485 U.S. at 656 n. 3, 108 S.Ct. at 1442 n. 3 (in finding that a claimed right was not implicit in Section 2, Eleventh, Supreme Court relies on the fact that Congress declined to enact proposed amendment that expressly would have established such right).
Section 2, Ninth was no insignificant piece of the 1934 amendments. Rather, as the legislative history makes clear, Congress thought it critical to establish machinery by which employees independently could choose their bargaining representatives. See H.R.Rep. No. 1944, 73d Cong., 2d Sess. 2 (1934), reprinted in 1 Railway Labor Aot, at 919; see also S.Rep. No. 1065, 73d Cong., 2d Sess., pt. 1, at 2 (1934), reprinted in 1 Rail*668way LABOR Act, at 821. For while the original legislation enacted in 1926 embodied the principle of free choice of employee representatives, it supplied no procedures to guarantee such choice. Experience had shown that railway management subverted their employees’ rights by “disputing the authority of the freely chosen representatives” to represent the employees. See H.R.Rep. No. 1944, at 2; see also Seoond Annual RepoRt of the National Mediation Board 2-3 (1936) (principal defect of the 1926 Act was failure to provide means to insure employees’ “right to select their representatives without influence or coercion from the management”). As the Board itself acknowledged in reflecting on pre-1934 history, “because employers have participated in” employee representation disputes, “bitter conflicts have often been precipitated.” First ANnual Report of the National Mediation Board 4 (1935).
It would be incongruous to suppose, in light of this demonstrated problem and in light of the fact that H.R. 7650 was rejected, that the Board has some unarticulated, inherent authority to entertain Section 2, Ninth petitions from carriers. By invoking the Board’s jurisdiction, a carrier could create a problem where employees saw none to exist or thrust itself into the center of a representation fray and thus attempt to influence the outcome of any subsequent election. For example, if the carrier petitioned for a Section 2, Ninth investigation very shortly after a challenging union began to court employee allegiance, that action could hasten an election and effectively prevent a serious challenge to the incumbent union. The timing of a carrier’s invocation easily might signal management’s sympathies and thus constitute forbidden “interference, influence, or coercion” over the employees’ designation of their representatives. 45 U.S.C. § 152 Third (1988). Such a scheme does not comport with the structure of the Act or with Congress’ clearly expressed intent.
A closely related concern animating the 1934 amendments was the problem of company unions. Although company-controlled unions were “clearly contrary to the purpose” of the 1926 Act, the practice continued because the Act did not include specific language which would, for example, bar carriers from paying the salaries of employee representatives. H.R.Rep. No. 1944, at 2. The 1934 amendments emphatically were intended to prohibit company unions. See 78 Cong. Reo. 11,713-14 (1934) (statement of sponsor Rep. Crosser); id. at 11,715 (statement of Rep. O’Connor). Thus, Section 2, Fourth spells out prohibitions on carrier conduct in some detail, providing, for example, that a carrier shall not “deny or in any way question the right of its employees to join [or] organize ... the labor organization of their choice....” 45 U.S.C. § 152 Fourth (1988). Section 2, Third also expressly prohibits “interference, influence, or coercion by either party over the designation” or choice of representatives by the other. Id. at § 152 Third. The concerns expressed by members of Congress and addressed in Section 2, Third and Fourth point strongly toward the conclusion that carriers were to be screened out of any active role in the representation-selection process, in order to avoid any possible tainting of employees’ free choice of representatives. See also International Ass’n of Machinists v. Street, 367 U.S. 740, 759, 81 S.Ct. 1784, 1795, 6 L.Ed.2d 1141 (1961) (“A primary purpose” of the 1934 amendments “was to strengthen the position of the labor organizations vis-a-vis the carriers”).
The legislative history further suggests that the sua sponte investigation power claimed by the Board is antithetical to congressional intent. Because mediation was considered to be the Board’s primary function, Congress sought to delineate the Board’s other roles in a manner that would avoid compromising its effectiveness as a mediator. It was for that reason, for example, that both the House and the Senate amended the originally-proposed text of Section 2, Ninth so as to empower the Board to appoint a neutral committee to resolve sensitive representation-related issues. See H.R. 7650 Hearings at 71 (“to have mediation what it ought to be,” Board “should have no power of decision save in the interpretation and administration of the law itself’) (statement of Samuel E. Winslow, Chairman of Board of Mediation); id. at 40-41 (statement of Commissioner Eastman); S.Rep. No. 1065, 73d Cong., 2d Sess., pt. 1, at 3 (1934), reprinted *669in 1 The Railway Laboe Act, at 822; accord Switchmen’s, 320 U.S. at 302-03, 64 S.Ct. at 98 (noting importance of maintaining Board’s neutrality). Cf. Chicago & N.W. Ry. Co. v. United Transp. Union, 402 U.S. 670, 580, 91 S.Ct. 1731, 1737, 29 L.Ed.2d 187 (1971) (significant concern was expressed during passage of 1926 Act that Board be able to “maintain the confidence of both” labor and management). The Merger Procedures trench on this carefully crafted structural scheme by robbing employees of their prerogative to determine whether and when formal procedures are needed to determine their representation. It takes little imagination to comprehend how quickly the Board could lose the confidence and trust of employees and labor organizations it dragged into unwanted elections. Thus, the Merger Procedures could well undermine the mediation effectiveness that Congress thought critical.
Tellingly, the Board cannot point to a single piece of the legislative history (let alone the text of the statute) that even remotely suggests it enjoys the sort of power it has claimed for itself under the Merger Procedures. To the contrary, by all indications, Congress thought the Board’s powers were not self-initiating, but were to be triggered by a proper invocation thereof by one of the employee parties to the dispute.8 See H.R. 7650 Hearings at 71 (Board should be kept “clean and free from everything that has gone on up to the time a dispute is actually brought to it ”) (statement of Samuel E. Win-slow) (emphasis added); id. at 79 (Board will investigate if representation “controversy is carried to the Board”) (statement of George M. Harrison) (emphasis added). Our review of the legislative history thus confirms our reading of the statutory text, and satisfies us that the Merger Procedures represent an unsustainable arrogation of power not conferred by Congress, and a “gross violation” of Section 2, Ninth by any reading of Leedom v. Kyne.9
C. The Board’s Consistent Interpretations and Practice
Although we find the language and legislative history dispositive, we briefly review the Board’s longstanding interpretation of Section 2, Ninth. We find it telling that only in the last five years of its sixty-year history has the Board claimed that Section 2, Ninth affords it the authority to initiate representation disputes or to permit carriers to do so. The Board fails to point to anything in its pre-Merger Procedures history that so much as hints at the existence of such “latent” authority. As such, the Merger Procedures are much more than a midstream change in course; they are a wholesale attempt to rewrite the statute and history.
We note in passing that the mere fact that the Board never before has claimed the authority embodied in the Merger Procedures does not mean that such authority, if granted by Congress, has ceased to exist. See United States v. Morton Salt Co., 338 U.S. 632, 647, 70 S.Ct. 357, 366, 94 L.Ed. 401 (1950). However, our analysis of the statute and the legislative history convinces us that Congress did not confer the powers claimed under Section 2, Ninth, in which case, of course, it goes without saying that the bald assertion of power by the agency cannot legitimize it. See id.
From its inception, the Board has understood Section 2, Ninth to screen carriers out of the certification proceedings: “The 1934 amendments give authority to the National Mediation Board to determine the choice of employee representatives without interference by management.... ” Second Annual *670REPORT OF THE NATIONAL MEDIATION BOARD 3 (1936) (emphasis added). See also FIRST Annual Report of the National Mediation Board 4 (1935) (Congress deliberately “eliminated [management], as a party, from any such controversy”). The Board, moreover, “has consistently interpreted the second and third general purpose of the act along with section 2, first and third, to exclude the carrier as a party to section 2, ninth, disputes,” 10 Thirty-Eighth Annual Report of the National Mediation Board 30 (1972), and it has reiterated that view even after promulgating the Merger Procedures. See Fifty-Fifth and Fifty-Sixth Annual Reports of the National Mediation Board 33 (1989-1990) (“Carriers are not a party to representation elections ... ”).
The Annual Reports and published Board decisions are equally telling for what they do not contain, namely, any suggestion that the Board itself has power to initiate a Section 2, Ninth investigation. Rather, the Board’s longstanding practice makes it clear that, until recently, there never has been even the slightest confusion over the limited authority of the NMB. See Dana E. Eischen, Representation Disputes and Their Resolution in the Railroad and Airline Industries, in The Railway Labor Act at Fifty 29 (1977) (Board, “with rare exceptions, has viewed its own role [under Section 2, Ninth] as narrowly circumscribed”). Regulations that have been in effect since 1947 clearly contemplate that representation investigations will be initiated only by employees or their representatives. See 29 C.F.R. § 1203.2 (1993) (requiring applications for Board services to be in writing and accompanied by signed authorization cards from employees); id. at § 1202.3 (Board shall investigate upon request of the parties). There simply is no suggestion that the Board may investigate under any other circumstances. See generally id. at §§ 1202.3-1202.8 (1993) (containing no suggestion of power to investigate representation disputes absent request of parties). Compare id. at § 1202.1 (Board “may proffer its [mediation] services” any time it finds a labor emergency).
Although we are not legally bound by the Board’s past constructions of Section 2, Ninth, it is surely noteworthy that these constructions do not in any way endorse the current position of the Board. For more than fifty years, the Board conducted representation investigations only upon request of employees, and the evidence indicates that the Board never even assumed that it had the authority to act sua sponte or at the request of a carrier.
D. The Board’s Claim of Implied Authority to Promulgate the Merger Procedures
As noted above, it is beyond cavil that “an agency’s power is no greater than that delegated to it by Congress.” Lyng v. Payne, 476 U.S. 926, 937, 106 S.Ct. 2333, 2341, 90 L.Ed.2d 921 (1986). The Board errs grossly in suggesting that “the question ... is whether the Act expressly precludes the Board from choosing” to adopt the Merger Procedures. Brief for National Mediation Board at 43. Quite to the contrary, the question is whether the Board’s “exercise of quasi-legislative authority” is “rooted in a grant of such power by the Congress and subject to limitations which that body imposes.” Chrysler Corp. v. Brown, 441 U.S. 281, 302, 99 S.Ct. 1705, 1718, 60 L.Ed.2d 208 (1979).
Unable to link its assertion of authority to any statutory provision, the Board’s position in this case amounts to the bare suggestion that it possesses plenary authority to act within a given area simply because Congress has endowed it with some authority to act in that area. We categorically reject that suggestion. Agencies owe their capacity to act to the delegation of authority, either express or implied, from the legislature. See Louisiana Pub. Serv. Comm’n v. FCC, 476 U.S. 355, 374, 106 S.Ct. 1890, 1901-02, 90 L.Ed.2d 369 (1986) (“an agency literally has no power to act ... *671unless and until Congress confers power upon it”); American Fin. Servs. Ass’n v. FTC, 767 F.2d 957, 965 (D.C.Cir.1985) (“The extent of [an agency’s] powers can be decided only by considering the powers Congress specifically granted it in the light of the statutory language and background.”) (citation omitted), cert. denied, 475 U.S. 1011, 106 S.Ct. 1185, 89 L.Ed.2d 301 (1986). The duty to act under certain carefully defined circumstances simply does not subsume the discretion to act under other, wholly different, circumstances, unless the statute bears such a reading. We cannot conclude, as the Board would have us do, that the fact that the Board is empowered to certify employee representatives in certain limited situations means the Board therefore enjoys such power in every instance in which a question of representation arguably exists. The language of Section 2, Ninth, the structure of the Act, and the legislative history all compel a contrary conclusion.
Nor is this a case in which principles of deference to an agency’s interpretation come into play. Such deference is warranted only when Congress has left a gap for the agency to fill pursuant to an express or implied “delegation of authority to the agency.” Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 843-44, 104 S.Ct. 2778, 2782, 81 L.Ed.2d 694 (1984). As we have already explained, “Congress has directly spoken to the precise question at issue” in this case, id. at 842, 104 S.Ct. at 2781, so there is no gap for the agency to fill. The text of Section 2, Ninth is plain; the legislative history and Supreme Court precedent underscore the limited role for carriers and for the Board under that section; and the Board can point to no contrary suggestion anywhere in its sixty-year history.
To suggest, as the Board effectively does, that Chevron step two is implicated any time a statute does not expressly negate the existence of a claimed administrative power (i.e. when the statute is not written in “thou shalt not” terms), is both flatly unfaithful to the principles of administrative law outlined above, and refuted by precedent. See, e.g., 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.’”) (quoting Kansas City v. Department of Housing & Urban Dev., 923 F.2d 188, 191-92 (D.C.Cir.1991)) (emphasis added). Were courts to presume a delegation of power absent an express withholding of such power, agencies would enjoy virtually limitless hegemony, a result plainly out of keeping with Chevron and quite likely with the Constitution as well.
Ill CONCLUSION
The judgment of the District Court dismissing RLEA’s complaint is hereby reversed. Case number 91-5223 is remanded for entry of declaratory and injunctive relief in favor of appellants; and case number 91-5310 is remanded for reconsideration in light of the new judgment in ease number 91-5223.
So Ordered.
. The separate concurring opinion by Judge Randolph holds that judicial review also is available to the appellants under section 704 of the Administrative Procedure Act, see 5 U.S.C. § 704 (1988), and that the Merger Procedures cannot withstand review for lack of authority in the Board to promulgate them. We agree with this alternative basis for decision.
. The Merger Procedures define "merger" broadly to include any "consolidation, merger, purchase, lease, operating contract, acquisition of control or similar transactions.” Merger Procedures, 17 N.M.B. at 50.
. RLEA also brought a second suit in the District Court, challenging the Board's application of the Merger Procedures. In that case, the Board, at the request of Burlington Northern Railroad Co. (“Burlington”), had investigated the effect of various mergers and consolidations, mostly dating back to the 1970s, on employee representation certifications. The Board investigated over eighty certifications, issuing some new ones and terminating others. See In re Merger of Northern Pacific Ry., 18 N.M.B. 240 (1991). The District Court also dismissed this suit for want of authority to review the Board's actions. See Railway Labor Executives’ Ass'n v. NMB, No. 91-1135, 1991 WL 190095 (D.D.C. Sept. 12, 1991) (order). The Burlington case was consolidated with this one on appeal before the panel as well as the en banc court.
. The cases cited by the Board do not establish a contrary proposition. They merely confirm that the judiciary takes a back seat when the Board decides matters that are "necessary incident[s]” of its right and duly to find the fact of representation. Railway Clerks, 380 U.S. at 669, 85 S.Ct. at 1202 (form of the election ballot); International Bhd. of Teamsters v. Brotherhood of Ry., Airline & S.S. Clerks, 402 F.2d 196, 202 (D.C.Cir.), cert. denied, 393 U.S. 848, 89 S.Ct. 135, 21 L.Ed.2d 119 (1968) (balloting policy).
. The dissent’s argument that "jurisdictional questions" are entitled to deference is misplaced. In making this argument, the dissent conflates reviewability under Switchmen’s and deference under Chevron. Were we to decide that all questions involving the Board’s exercise of jurisdiction under Section 2, Ninth were reviewable, that would not answer the question whether the exercise were proper; and, in some cases, we might well defer to the Board’s construction of the RLA. In this case, the reason no deference is warranted is because we find no ambiguity in Section 2, Ninth. See Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 843-44, 104 S.Ct. 2778, 2782, 81 L.Ed.2d 694 (1984) (courts should defer to an agency's reasonable statutory construction only when Congress has left a gap for the agency to fill).
. We note that the Board itself relies on precisely the same sort of negative inference to argue that Congress "knew how to preclude authority that might otherwise be inferred." Brief for National Mediation Board at 39 n. 24. The Board's argument leads nowhere, however, in light of the text of the statute, the legislative history, and the principle that agencies act only pursuant to delegations of power that are explicit or can fairly be implied. See American Fin. Servs. Ass’n v. FTC, 767 F.2d 957, 965 (D.C.Cir.1985), cert. denied, 475 U.S. 1011, 106 S.Ct. 1185, 89 L.Ed.2d 301 (1986). The Board seems not to understand that "an agency’s power is no greater than that delegated to it by Congress.” Lyng v. Payne, 476 U.S. 926, 937, 106 S.Ct. 2333, 2341, 90 L.Ed.2d 921 (1986).f
. The House of Representatives ultimately passed H.R. 9861, a successor to H.R. 7650, which incorporated Section 2, Ninth as drafted by Commissioner Eastman and contained in H.R. 9689. Only H.R. 7650 contained a Section 2, Eighth that included carriers as parties to disputes.
. We are neither troubled nor persuaded by the Board's insistence that our "literal” reading of Section 2, Ninth would preclude unions from invoking the Board's jurisdiction, as has long been the practice. It is clear that in applying for investigation of a representation dispute, unions act only on behalf of employees, not as "parties” in their own right. See, e.g., 29 C.F.R. § 1203.2 (1993) (written applications for investigation of representation disputes “should be accompanied by signed authorization cards from the employees composing the craft or class involved in the dispute”).
. In light of our conclusion that Section 2, Ninth permits only employees to invoke the Board's jurisdiction, we find it unnecessary to reach RLEA's additional contention that there is no "dispute” within the meaning of that section when the carrier or the Board initiates a Section 2, Ninth investigation.
. The second and third general purposes of the Act are "(2) to forbid any limitation upon freedom of association among employees or any denial, as a condition of employment or otherwise, of the right of employees to join a labor organization; [and] (3) to provide for the complete independence of carriers and of employees in the matter of self-organization to cariy out the purposes of this chapter_" 45 U.S.C. § 151a.