The Supreme Court upheld the right of disabled people to sue state governments that fail to provide ramps, elevators or other forms of access to their courthouses yesterday -- a clear but limited victory for the disability rights movement that blunts a trend at the court in favor of states' rights.

By a vote of 5 to 4, the court ruled that the Americans With Disabilities Act (ADA), adopted by Congress in 1990 and signed into law by President George H.W. Bush, provides a proper basis for a federal lawsuit in which paraplegics George Lane and Beverly Jones are seeking money damages from Tennessee for its alleged failure to accommodate them at various courthouses.

Lane said that, on one occasion, he had to crawl up the front stairs of the Polk County courthouse to face a hearing on misdemeanor charges.

Noting a historical "pattern of disability discrimination" in the administration of justice by the states, Justice John Paul Stevens wrote for the majority that Title II of the ADA, which mandates equal treatment for the disabled in public "services, programs and activities," was a valid use of Congress's power to define unconstitutional behavior by the states and to prevent violations by lifting the states' sovereign immunity to suits for damages.

The ruling makes it possible for disabled people to sue for money in a federal court when they feel that a state government has wrongfully refused to make its courts fully accessible.

Disability rights advocates, supported in this case by the Bush administration, had sought a much broader ruling that would have upheld the use of Title II against the states in all public services, activities and programs.

Stevens wrote that the ruling was limited "to the class of cases implicating the fundamental right of access to the court," leaving other issues -- such as access to state-run swimming pools or hockey rinks -- for another day.

His opinion also noted that the states, some of which are dotted with older courthouses that would be costly to renovate, are not obliged to assume "an undue financial or administrative burden" or to cast aside historic preservation interests.

The crucial fifth vote for Stevens's opinion came from Justice Sandra Day O'Connor, a moderate conservative who is a strong supporter of the court's recent states' rights rulings -- and cool to disability rights claims.

Some saw the limitations in the court's ruling as concessions to keep O'Connor in the majority, whose other members, liberals David H. Souter, Ruth Bader Ginsburg and Stephen G. Breyer, have supported a broad reading of disability laws -- and opposed the court's states' rights decisions.

"Basically, the court is saying that the courthouse doors must be open to those of us with disabilities," said former House majority whip Tony Coelho, a Democrat who played a leading role in drafting the ADA. "But . . . it is obvious that this decision is restricted to court access in order to get Justice O'Connor's vote."

The 14th Amendment to the Constitution, enacted after the Civil War to secure the rights of newly freed African Americans, says that each state will guarantee due process and "the equal protection of the laws." It empowers Congress to enforce that guarantee through "appropriate legislation."

The current court is sharply divided over what legislation is "appropriate."

Liberals such as Stevens, Souter, Ginsburg and Breyer argue that the 14th Amendment means Congress can act fairly freely, on behalf of the nation as a whole, against state discrimination based not only on race but on age, gender or disability as well. They have expressed concern that the conservatives want to roll back much of the court's modern individual rights jurisprudence.

But conservatives, led by Chief Justice William H. Rehnquist, have argued that the states enjoy a strong presumption of immunity to federal lawsuits, and that the 14th Amendment empowers Congress to enact only carefully tailored laws against long-standing and well-documented state violations.

Conservatives insist that proscriptions against racial discrimination would survive this test, but that the Constitution gives the Supreme Court, not Congress, the final say as to what unconstitutional action is bad enough to trump state immunity. In recent years, for example, the court has ruled that the ADA cannot apply to state employment.

O'Connor has generally supported those rulings. But last year, she defected from the states' rights camp for the first time, voting to uphold lawsuits against states under the federal Family and Medical Leave Act. Rehnquist also joined the majority in that 6 to 3 ruling, writing an opinion that said the act was aimed at well-documented gender discrimination in the allocation of employee leave.

But yesterday, Rehnquist dissented, as did Justices Antonin Scalia, Anthony M. Kennedy and Clarence Thomas.

Rehnquist charged that the majority had failed to show that inaccessible courthouses had resulted in truly widespread violations of disabled people's constitutional rights by the states.

In Title II, Rehnquist wrote, "Congress has authorized private damages suits against a State for merely maintaining a courthouse that is not readily accessible to the disabled, without regard to whether a disabled person's due process rights are ever violated."

He noted that George Lane had been arrested for missing a court date only after he refused help to get up the stairs, and that Lane refused an offer to move the case to an accessible court nearby.

The case is Tennessee v. Lane, No. 02-1667.