Those passengers said that they paid premiums to the Norwegian Cruise Line for handicapped-accessible cabins and the assistance of crew but that the cruise line failed to configure restaurants, swimming pools, elevators, and public bathrooms.
The case may have significant implications for cruise lines, which could be forced to retrofit ships. The worldwide industry estimates that two-thirds of its passengers are Americans.
Goldstein said the National Labor Relations Act doesn't apply to the crews of foreign-flagged vessels that stop in US ports, ''but when Americans are involved" circumstances change.
The justices seemed concerned about stepping into a case involving the law of the sea, US rules, and the regulations of foreign countries.
''You are saying the US rules the world," Justice Ruth Bader Ginsburg told Goldstein.
The passengers drew support for their position from the Justice Department, which says the disabilities act applies.
The justices put David Frederick, a lawyer for the cruise line, in the uncomfortable position of saying a landmark US civil rights law prohibiting discrimination against African-Americans doesn't apply to foreign-flagged vessels stopping in American ports because there is no specific language in the law that says so.
Frederick said the civil rights laws of the country where a ship is registered apply.
Stretching the ADA to cover foreign-flagged ships puts the courts in the position of becoming ''a special master for the cruise industry," Frederick said. ''This court need not open up a Pandora's box of regulation."
Applying the disabilities act would ''wreak havoc" and ''invite the sort of international discord that Congress seeks to avoid," Gregory Garre, a lawyer representing the Bahamas, told the court.
Much of the industry registers its ships away from home countries in places such as the Bahamas, Liberia, Honduras, Panama, and Cyprus, which tout business-friendly regulations. The US cruise industry is almost exclusively foreign-flagged.
Flags of convenience, as they are known, offer cruise ship operators the advantages of lower wages and fewer taxes.
Justice Antonin Scalia disputed the assertion that there is no clear language in the disabilities act that applies it to cruise ships.
Justice Stephen G. Breyer expressed two concerns: applying the law to ships that rarely visit US ports and not applying the disabilities act when, by the industry's own estimates, most of its customers are Americans.
The cruise lines and disability groups had urged the Supreme Court to take the case, contending that federal appeals courts in Louisiana and Florida reached opposite conclusions on whether the disabilities act applies to the industry.
