with whom Mr. Justice Brennan joins, dissenting.
For over 140 years, the Court has resolved ambiguities in statutes, documents, and treaties that affect retained tribal sovereignty in favor of the Indians.1 This interpretive prin*503ciple is a response to the unique relationship between the Federal Government and the Indian people, “who are the wards of the nation, dependent upon its protection and good faith.” Carpenter v. Shaw, 280 U. S. 363, 367 (1930). More fundamentally, the principle is a doctrinal embodiment of “the right of [Indian nations] to make their own laws and be ruled by them,” Williams v. Lee, 358 U. S. 217, 220 (1959), a right emphatically reaffirmed last Term in United States v. Wheeler, 435 U. S. 313, 322-330 (1978). Although retained tribal sovereignty “exists only at the sufferance of Congress,” id., at 323, the States may not encroach upon an Indian nation's internal self-government until Congress has unequivocally sanctioned their presence within a reservation. See ibid.; McClanahan v. Arizona State Tax Comm’n, 411 U. S. 164, 168-169, 172-173); Worcester v. Georgia, 6 Pet. 515, 554, 557, 561 (1832); see also Oliphant v. Sugwamish Indian Tribe, 435 U. S. 191, 212 (1978) (Marshall, J., dissenting).
While the Court in its discussion of the disclaimer issue professes to follow this settled principle of statutory interpretation, ante, at 484, it completely ignores the rule when addressing Washington’s assertion of partial jurisdiction. In my view, the language and legislative history of Pub. L. 280 do not unequivocally authorize States to assume the type of selective geographic and subject-matter jurisdiction that Washington asserted in 1963.2 Because our precedents compel *504us to construe the statute in favor of the Indians, I respectfully dissent.
As is evident from the majority opinion, the text of Pub. L. 280 does not on its face empower option States to assert partial geographic or subject-matter jurisdiction over Indian reservations.3 The statute refers without limitation to “criminal” and “civil” jurisdiction. Nevertheless, because option States could have conditioned their exercise of full jurisdiction on the consent of affected tribes, ante, at 495, 498, and because Pub. L. 280 would have permitted Washington to extend full jurisdiction over the Yakima Indian Reservation without consulting the Tribe, ante, at 499, the Court concludes that the States can unilaterally assert less than full jurisdiction.
I agree that Pub. L. 280 permits option States to refuse jurisdiction absent the consent of the Indians, and that prior to the 1968 amendments of the Act,4 Washington could have unilaterally extended full jurisdiction over the Reservation. But the majority does not explain how the statutory language governing exercise of full jurisdiction allows the States to exercise piecemeal jurisdiction. That Washington has done no more than “refrain from exercising the full measure of allowable jurisdiction,” ante, at 495, raises but does not answer *505the critical question whether Pub. L. 280 sanctions this jurisdictional arrangement.
The sparse legislative history of Pub. L. 280, like the statutory language, says nothing about the propriety of partial jurisdictional schemes. In light of the expressed reluctance of at least one State to assume the financial burden that jurisdiction over Indian territory entails,5 this silence is particularly instructive. Although selective assertion of jurisdiction within reservations would obviously ameliorate such fiscal concerns, at no point in the congressional deliberations was it advanced as a solution. Rather, Congress permitted the option States to refrain from exercising full jurisdiction until they could meet their financial obligations.6 The legislative focus was clearly on full-fledged assumption of jurisdiction.7
To disregard this legislative focus and allow assumption of partial jurisdiction undermines an important purpose behind Pub. L. 280. In enacting the statute, Congress sought to eliminate the serious “hiatus in law-enforcement authority” on Indian reservations, H. R. Rep. No. 848, supra n. 5, at 6, which was attributable in large part to the division of law enforcement functions among federal, state, and Indian authorities.8 It intended to accomplish this goal by granting *506to the States the authority previously exercised by the Federal Government, thereby simplifying the administration of law on Indian reservations. See 1953 Subcommittee Hearings 7. Washington’s complex jurisdictional system, dependent on the status of the offender, the location of the crime, and the type of offense involved, by no means simplifies law enforcement on the Yakima Reservation. Cf. 1 National American Indian Court Judges Assn., Justice and the American Indian: The Impact of Public Law 280 upon the Administration of Justice on Indian Reservations 6-13 (1974). To the contrary, it exacerbates the confusion that the statute was designed to redress.
Had Congress intended to condone exercise of limited subject-matter jurisdiction on a random geographic basis, it could have easily expressed this purpose. See Bryan v. Itasca County, 426 U. S. 373, 392-393 (1976); Matts v. Arnett, 412 U. S. 481, 504-505 (1973); McClanahan v. Arizona State Tax Comm’n, 411 U. S., at 173-175, and n. 13; Menominee Tribe of Indians v. United States, 391 U. S. 404, 412-413 (1968); Creek County Comm’rs v. Seber, 318 U. S. 705, 713 (1943). Indeed, it did so in the 1968 amendments to the Act when it authorized partial criminal or civil jurisdiction by subject matter, geography, or both, but only with the Indians’ consent. 25 U. S. C. §§ 1321 (a), 1322 (a).9 I am unwilling to *507presume that Congress’ failure in 1953 to sanction piecemeal jurisdiction in similar terms was unintentional. In any event, it is indisputable that the statute does not unambiguously authorize assertion of partial jurisdiction. If we adhere more than nominally to the practice of resolving ambiguities in favor of the Indians, then Washington’s jurisdictional arrangement cannot stand.
Accordingly, I dissent.
E. g., Worcester v. Georgia, 6 Pet. 515, 580-582 (1832) (McLean, J., concurring); The Kansas Indians (Wan-zop-e-ah v. Board of Comm’rs *503of the County of Miami), 5 Wall. 737, 760 (1867); Jones v. Meehan, 175 U. S. 1, 11-12 (1899); Cherokee Intermarriage Cases, 203 U. S. 76, 94 (1906); Choate v. Trapp, 224 U. S. 665, 675 (1912); Alaska Pacific Fisheries v. United States, 248 U. S. 78, 89 (1918); Carpenter v. Shaw, 280 U. S. 363, 366-367 (1930); United States v. Santa Fe Pacific R. Co., 314 U. S. 339, 353-354 (1941); Squire v. Capoeman, 351 U. S. 1, 6-7 (1956); Menominee Tribe of Indians v. United States, 391 U. S. 404, 406 n. 2 (1968); McClanahan v. Arizona State Tax Comm’n, 411 U. S. 164, 173-175, and n. 13 (1973); Bryan v. Itasca County, 426 U. S. 373, 392-393 (1976).
Since I would invalidate Washington’s jurisdictional arrangement on this ground, I need not address the disclaimer issue. For present pur*504poses I will assume that Washington was not required, to amend its constitutional disclaimer of authority over Indian lands before it could exercise power over the Reservation.
It may be that the disjunctive language of § 7 allows option States to exercise either criminal or civil jurisdiction. See ante, at 496-497, and n. 41. And perhaps extension of jurisdiction reservation by reservation is also permissible. See ante, at 494 n. 41. But neither of these questions is posed by this case. The issue presented here is whether the language of Pub. L. 280 authorizes any patchwork jurisdictional arrangement that suits the States’ peculiar interests.
These amendments prohibit States from exercising further jurisdiction over Indian reservations after 1968 without tribal consent. 25 U. S. C, §§1321 (a), 1322 (b), 1326.
See Hearings on H. R. 1063 before the Subcommittee on Indian Affairs of the House Committee on Interior and Insular Affairs, 83d Cong., 1st Sess., 8-10, 14r-15 (1953) (hereinafter 1953 Subcommittee Hearings); Hearings on H. R. 1063 before the House Committee on Interior and Insular Affairs, 83d Cong., 1st Sess., 3, 7, 13, 17 (1953) (hereinafter 1953 Committee Hearings); H. R. Rep. No. 848, 83d Cong., 1st Sess., 7 (1953).
See 1953 Committee Hearings 13; H. R. Rep. No. 848, supra, at 6-7.
See, e. g., 1953 Subcommittee Hearings 3, 4, 5, 7, 17; 1953 Committee Hearings 3, 8; 99 Cong. Rec. 10782-10783 (1953) (statement of Sen. Thye; letter from Gov. Anderson to Sen. Thye).
See H. R. Rep. No. 848, supra, at 5-6; 1953 Subcommittee Hearings 2-3, 21-22; Hearings on H. R. 459, H. R. 3235 and H. R. 3624 before the Subcommittee on Indian Affairs of the House Committee on Interior and *506Insular Affairs, 82d Cong., 2d Sess., 14 (1952) (statement of Rep. D’Ewart); Goldberg, Public Law 280: The Limits of State Jurisdiction Over Reservation Indians, 22 UCLA L. Rev. 535, 541-543 (1975).
The legislative history of the 1968 amendments provides further evidence that Congress in 1953 did not unambiguously sanction assertion of selective jurisdiction. There were numerous conflicting opinions on whether the new provisions authorizing States to assume partial jurisdiction effected a change in the law. In 1965, the Department of the Interior had intimated that partial assumption of criminal jurisdiction was a novel idea when it recommended partial jurisdiction in civil matters, but concluded that “extension of criminal jurisdiction to the States on a piecemeal basis needs to be considered further.” Hearings on Constitutional Rights of the American Indian before the Subcommittee on Constitutional *507Rights of the Senate Committee on the Judiciary, 89th Cong., 1st Sess., 321 (1965) (letter from Frank J. Barry, Acting Secy, of the Interior, to Sen. Eastland). This letter also noted that the Department of Justice was opposed to selective extensions of criminal jurisdiction because of the likelihood of unnecessary confusion in the enforcement of criminal laws. Ibid.
However, in 1968, Assistant Secretary of the Interior Harry R. Anderson believed that authority to assume piecemeal jurisdiction was implicit in Pub. L. 280. Hearings on H. R. 15419 and Related Bills before the Subcommittee on Indian Affairs of the House Committee on Interior and Insular Affairs, 90th Cong., 2d Sess., 25 (1968) (letter to Rep. Wayne N. Aspinall). By contrast, Congressman Aspinall, who played a fundamental role in drafting Pub. L. 280, stated that the new partial-jurisdiction provisions substantially altered prior law. 114 Cong. Rec. 9615 (1968). Similarly, Arthur Lazarus, an attorney representing six Tribes, argued that “[o]ne of the major objections to Public Law 280 is its ‘all or nothing’ approach, requiring States to assume all jurisdiction on Indian reservations if any jurisdiction is desired.” 1968 Hearings, supra, at 116. Deputy Attorney General Warren Christopher was noncommittal on the reading of prior law. Id., at 28 (letter to Rep. Aspinall).
This subsequent legislative consideration of the precise issue before us sheds light on the intent of Congress in 1953. See Mattz v. Arnett, 412 U. S. 481, 505 n. 25 (1973); Moe v. Salish & Kootenai Tribes, 425 U. S. 463, 472-475 (1976); Bryan v. Itasca County, 426 U. S., at 386. Given the congressional and executive equivocation, the Court’s apparent certainty is unfounded.