ASHINGTON, Jan. 13 — In 1990, when Congress passed the Americans With Disabilities Act and placed new obligations on state governments to remove barriers to accessibility, the Supreme Court's revival of interest in states' rights still lay a few years in the future. Few people would have predicted the coming collision between the new law and the new federalism.

But the clash was on full display on Tuesday in the courtroom. In a case from Tennessee, the justices heard arguments on whether the states are constitutionally immune from the damage suits that the law authorizes for failure to make public services, programs and activities accessible to people with disabilities.

The state was sued by six people who could not gain unassisted access to county courthouses that lacked elevators, including one man, George Lane, who left his wheelchair and crawled up two flights of stairs to attend his own arraignment on a misdemeanor traffic charge in the Polk County Courthouse in Benton.

The testy argument made it clear that the decision was not going to be an easy one for a court that has been sharply divided in a series of state immunity cases. But if the damages question was not contentious enough, beyond it lay a deeper issue, discussed only obliquely but clearly on the minds of the justices and the lawyers — whether Congress had authority to apply the disabilities act to the states in the first place.

A complex web of recent constitutional doctrine surrounds this case, Tennessee v. Lane, No. 02-1667. The court's recent precedents have limited the ability of Congress to make federal laws binding on the states. Congress can breach the states' constitutional immunity from damage suits, the court has ruled, only by invoking its power under the 14th Amendment to enforce, by "appropriate" legislation, the amendment's guarantees of due process and equal protection. Legislation will be deemed appropriate under these precedents only if it remedies a documented pattern of constitutional violations by the states.

Against that background, much of the focus of the argument on Tuesday was on how to characterize a state's failure to make its services accessible to people with disabilities. Architectural barriers to entering a courthouse do not amount to a constitutional violation "even under the most creative interpretation," the solicitor general of Tennessee, Michael E. Moore, told the court. Mr. Moore said that "in the myriad contexts to which it applies," the law "imposes obligations on the states that go far beyond what the Constitution itself requires."

Mr. Moore said Mr. Lane was offered accommodations to enable him to go to his hearing, including being carried upstairs or having the hearing moved to the ground floor. "So long as the court in question offers its service in an authorized venue," there is no violation, he said.

William J. Brown, the lawyer for Mr. Lane and the five other plaintiffs, said that to the contrary, the purpose of the law was to ensure that people with disabilities do not have to "suffer pain and public humiliation as a condition of citizenship." The Constitution protects the right of access to a courtroom, Mr. Brown said, adding: "We all have a right to get to the civic center of our public life."

The Bush administration entered the case to defend the law. Paul D. Clement, a deputy solicitor general, said this case should not be governed by a decision in 2001 that held the states to be immune from suit by their employees for violations of a separate section of the disabilities act that bars employment discrimination. Mr. Clement said that although states' employment discrimination might not have been well documented, Congress's decision to open the states to suit under the public services section was based on a finding of "persistent discrimination in critical areas."

"That depends on what is meant by the term `discrimination,' " Justice Antonin Scalia said.

Mr. Clement replied that Congress had found examples of inaccessible polling places that deprived people with disabilities of the right to vote.

"An inaccessible voting place proves nothing at all," Justice Scalia said. "It just shows that the state didn't go out of its way" to provide help.

Mr. Moore, the Tennessee solicitor general, emphasized the breadth of the law and what he described as "its indiscriminate application to every facet" of state activities. Several justices readily agreed. When Mr. Clement said that it was "clear that Congress was reacting to a real problem," Justice Scalia interjected with evident sarcasm, saying, "And it solved that problem by requiring access to state-owned hockey rinks."

The outcome of the case could well depend on how the court chooses to frame the question: whether the justices look at the particular situation of access to court, or whether they look at the full breadth of the statute. The United States Court of Appeals for the Sixth Circuit, which sits in Cincinnati, rejected Tennessee's immunity claim on the ground that access to court was a due process right deserving of special solicitude.

But Chief Justice William H. Rehnquist observed that the court had typically examined statutes as a whole rather than by particular applications.

The deeper issue was what the consequences might be if the court decided that the public services part of the law exceeded Congress's authority under the 14th Amendment. As an alternative basis for the disabilities act, Congress also invoked its power to regulate interstate commerce, a power that clearly justifies, for example, prohibiting discrimination in employment. It is less clear whether the commerce power extends to essentially noneconomic activities like access to courthouses or voting booths.