Opinion of SCALIA, J. significant authority to regulate activities in the waters of Glacier Bay by virtue of its dominant navigational servitude, other aspects of the Commerce Clause, and even the treaty power. See, e. g., 43 U. S. C. § 1314(a) (under the Submerged Lands Act, the United States retains "powers of regulation and control of . . . navigable waters for the constitutional purposes of commerce [and] navigation"); United States v. Morrison, 529 U. S. 598, 609 (2000) (Congress may "regulate the use of the channels of interstate commerce" and "protect the instrumentalities of interstate commerce, or persons or things in interstate commerce" (internal quotation marks omitted)); United States v. Alaska, 503 U. S. 569, 577-583 (1992) (the Secretary of the Army may consider effects upon recreation, fish and wildlife, natural resources, and other public interests when refusing to permit structures or discharges in navigable waters that have "no effect on navigation"); United States v. California, 436 U. S. 32, 41, and n. 18 (1978) (noting that the United States retained "its navigational servitude" even when California took the "proprietary and administrative interests" in submerged lands surrounding islands in a national monument); Douglas v. Seacoast Products, Inc., 431 U. S. 265, 284-287 (1977) (finding 3 The United States presented evidence that, even before the Monument was established, some scientists had studied the bottom of Glacier Bay and its relationship with the glaciers by taking soundings of the water's depth. Memorandum in Support of Motion of the United States for Partial Summary Judgment on Count IV of the Amended Complaint 13. Similar but more sophisticated studies, involving acoustic mapping and sonar imaging of gouges in the floor of the bay, are conducted today. App. 5 to Declaration of Tomie Patrick Lee, Exhibits to Reply of United States in Support of Motion for Partial Summary Judgment on Count IV of Amended Complaint, Tab No. 8, pp. 93-94 (Exh. U. S. IV-8). Alaska's ownership of submerged lands should not hinder such studies, generally conducted from vessels on the water's surface. But the United States also noted that other, newer means of scientific study-such as withdrawing core samples from submerged lands and installing listening devices on the surface of submerged lands-would require Alaska's cooperation. Tr. of Oral Arg. 40. Opinion of SCALIA, J. state regulation of commercial fishing partially pre-empted by federal statute); Letter from W. C. Henderson, Acting Chief, Bureau of Biological Survey, Dept. of Agriculture, to Stephen T. Mather, Director, National Park Service (Nov. 4, 1926), Alaska Exh. AK-405 (noting that a colony of eider ducks in and near the Monument was "protected at all times by the Migratory Bird Treaty Act and Regulations thereunder"). It is thus unsurprising that States own submerged lands in other federal water parks, such as the California Coastal National Monument and the Boundary Waters Canoe Area in Minnesota. See California, supra, at 37; Brief for National Parks Conservation Association as Amicus Curiae 30. I would probably find for Alaska on the Glacier Bay issue even if the United States did not have to overcome the obstacle of "very plain" retention. With the addition of that well-established requirement, the case is not even close. Because neither text, nor context, nor precedent compels the conclusion that the Alaska Statehood Act expressly retained the Monument's submerged lands for the United States, I cannot agree with the Court's conclusion that the United States deserves summary judgment on count IV of Alaska's amended complaint. Syllabus SPECTOR ET AL. v. NORWEGIAN CRUISE LINE LTD. CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH CIRCUIT No. 03-1388. Argued February 28, 2005-Decided June 6, 2005 Respondent NCL is a cruise line operating foreign-flag ships departing from, and returning to, United States ports. The petitioners, disabled individuals and their companions who purchased tickets for round-trip NCL cruises from Houston, sued NCL under Title III of the Americans with Disabilities Act of 1990 (ADA), 42 U. S. C. § 12181 et seq., which prohibits discrimination based on disability in places of "public accommodation," § 12182(a), and in "specified public transportation services," § 12184(a), and requires covered entities to make "reasonable modifications in policies, practices, or procedures" to accommodate disabled persons, §§ 12182(b)(2)(A)(ii), 12184(b)(2)(A), and to remove "architectural barriers, and communication barriers that are structural in nature," where such removal is "readily achievable," §§ 12182(b)(2)(A)(iv), 12184(b)(2)(C). Though holding Title III generally applicable, the District Court found that the petitioners' claims regarding physical barriers to access could not go forward because the federal agencies charged with promulgating ADA architectural and structural guidelines had not done so for cruise ships. The court therefore dismissed the barrierremoval claims, but denied NCL's motion to dismiss the petitioners' other claims. The Fifth Circuit held that Title III does not apply to foreign-flag cruise ships in U. S. waters because of a presumption, which the court derived from, e. g., Benz v. Compania Naviera Hidalgo, S. A., 353 U. S. 138, and McCulloch v. Sociedad Nacional de Marineros de Honduras, 372 U. S. 10, that absent a clear indication of congressional intent, general statutes do not apply to foreign-flag ships. Emphasizing that Title III does not contain a specific provision mandating its application to such vessels, the court sustained the dismissal of the petitioners' barrier-removal claims and reversed on their remaining claims. Held: The judgment is reversed, and the case is remanded. 356 F.3d 641, reversed and remanded. JUSTICE KENNEDY delivered an opinion concluding that except insofar as Title III regulates a vessel's internal affairs, the statute is applicable to foreign-flag cruise ships in U. S. waters. Parts II-A-1 and II-B-2 of that opinion held for the Court: (a) Although Title III's "public accommodation" and "specified public transportation" definitions, §§ 12181(7)(A), (B), (I), (L), 12181(10), do not Syllabus expressly mention cruise ships, there is no doubt that the NCL ships in question fall within both definitions under conventional principles of interpretation. The Fifth Circuit nevertheless held Title III inapplicable because the statute has no clear statement or explicit text mandating coverage for foreign-flag ships in U. S. waters. This Court's cases, particularly Benz and McCulloch, do hold, in some circumstances, that a general statute will not apply to certain aspects of the internal operations of foreign vessels temporarily in U. S. waters, absent a clear statement. The broad clear statement rule adopted by the Court of Appeals, however, would apply to every facet of the business and operations of foreign-flag ships. That formulation is inconsistent with the Court's case law and with sound principles of statutory interpretation. Pp. 128-130. (b) Title III defines "readily achievable" barrier removal as that which is "easily accomplishable and able to be carried out without much difficulty or expense," § 12181(9). The statute does not further define "difficulty," but the section's use of the disjunctive indicates that it extends to considerations in addition to cost. Furthermore, Title III directs that the "readily achievable" determination take into account "the impact... upon the [facility's] operation," § 12181(9)(B). A Title III barrier-removal requirement that would bring a vessel into noncompliance with the International Convention for the Safety of Life at Sea or any other international legal obligation would create serious difficulties for the vessel and would have a substantial impact on its operation, and thus would not be "readily achievable." Congress could not have intended this result. It is logical and proper to conclude, moreover, that whether a barrier modification is "readily achievable" must take into consideration the modification's effect on shipboard safety. Title III's nondiscrimination and accommodation requirements do not apply if disabled individuals would pose "a significant risk to the health or safety of others that cannot be eliminated by a modification of policies, practices, or procedures." §12182(b)(3). It would be incongruous to attribute to Congress an intent to require modifications threatening others' safety simply because the threat comes not from the disabled person but from the accommodation itself. Pp. 135–136. JUSTICE KENNEDY, joined by JUSTICE STEVENS and JUSTICE SOUTER, concluded in Parts II-A-2, II-B-1, II-B-3, and III-B: (a) As a matter of international comity, a clear statement of congressional intent is necessary before a general statutory requirement can interfere with matters that concern a foreign-flag vessel's internal affairs and operations. See, e. g., Wildenhus's Case, 120 U. S. 1, 12. In Benz and McCulloch, the Court held the National Labor Relations Act (NLRA) inapplicable to labor relations between a foreign vessel and its Syllabus foreign crew not because foreign ships are generally exempt from the NLRA, but because that particular application of the NLRA would interfere with matters that concern only the ship's internal operations. These cases recognized a narrow rule, applicable only to statutory duties that implicate the foreign vessel's internal order rather than the welfare of American citizens. E. g., McCulloch, supra, at 21. In contrast, the Court later held the NLRA fully applicable to labor relations between a foreign vessel and American longshoremen because this relationship, unlike the one between a vessel and its own crew, does not implicate a foreign ship's internal order and discipline. Longshoremen v. Ariadne Shipping Co., 397 U. S. 195, 198-201. This narrow clear statement rule is supported by sound principles of statutory construction. It is reasonable to presume Congress intends no interference with matters that are primarily of concern only to the ship and the foreign state in which it is registered. It is also reasonable, however, to presume Congress does intend its statutes to apply to entities in U. S. territory that serve, employ, or otherwise affect American citizens, or that affect the peace and tranquility of the United States, even if those entities happen to be foreign-flag ships. Cruise ships flying foreign flags of convenience but departing from and returning to U. S. ports accommodate and transport over 7 million U. S. residents annually, including large numbers of disabled individuals. To hold there is no Title III protection for the disabled would be a harsh and unexpected interpretation of a statute designed to provide broad protection for them. Pp. 130-133. (b) Plainly, most of the Title III violations alleged below-that NCL required disabled passengers to pay higher fares and special surcharges; maintained evacuation programs and equipment in locations not accessible to them; required them, but not other passengers, to waive any potential medical liability and to travel with companions; reserved the right to remove them from ships if they endangered other passengers' comfort; and, more generally, failed to make reasonable modifications necessary to ensure their full enjoyment of the services offered-have nothing to do with a ship's internal affairs. However, the petitioners' allegations concerning physical barriers to access on board-e. g., their assertion that most of NCL's cabins, including the most attractive ones in the most desirable locations, are not accessible to disabled passengers-would appear to involve requirements that might be construed as relating to internal ship affairs. The clear statement rule would most likely come into play if Title III were read to require permanent and significant structural modifications to foreign vessels. Pp. 133-135. (c) Because Title III does not require structural modifications that conflict with international legal obligations or pose any real threat to the safety of the crew or other passengers, it may well follow that Title |