WASHINGTON-The Americans with Disabilities Act does not override company seniority systems under most circumstances, a divided Supreme Court ruled last week.

But the high court's decision in US Airways Inc. vs. Robert Barnett last week may not be unalloyed good news for employers, legal experts on both sides of the issue say. In fact, it's likely to open the door to more litigation, they say.

At issue was whether the ADA gave Mr. Barnett precedence over workers with more seniority when he sought to keep a mailroom job he'd been transferred to after he injured his back as a baggage handler. The ADA prohibits an employer from discriminating against a worker with a disability who, with "reasonable" accommodations, can perform a job.

Mr. Barnett lost the mailroom job when workers with more seniority applied for it, and, in 1994, he sued his employer under the ADA.

Eventually, the case went before the 9th U.S. Circuit Court of Appeals, which held that US Airways couldn't deny Mr. Barnett the job solely on the grounds that allowing him to stay in the position would undermine the company's seniority system. US Airways appealed to the Supreme Court.

Writing for the majority in the high court's 5-4 decision, Associate Justice Stephen Breyer said, "The seniority system will prevail in the run of cases."

"A showing that the arrangement would violate the rules of a seniority system warrants summary judgment for the employer-unless there is more. The plaintiff must present evidence of that `more,' namely, special circumstances surrounding the particular case that demonstrate the arrangement is nonetheless reasonable," Justice Breyer wrote. Elsewhere in the decision, Justice Breyer noted as an example that a plaintiff might be able to demonstrate "the system already contains exceptions such that, in the circumstances, one further exception is unlikely to matter."

The high court remanded Mr. Barnett's case to a lower court.

The decision drew two dissenting opinions. In one, Associate Justices Antonin Scalia and Clarence Thomas argued that the decision did not give employers enough protection in such cases. The other dissent, filed by Associate Justices David Souter and Ruth Bader Ginsburg, argued that the majority had not given workers enough protection.

Employment law experts view the decision as generally favorable to employers, but they offer caveats.

"The Supreme Court's decision gives employers with collectively bargained seniority systems a presumed trump card to overcome an employee's request to override a seniority system's provisions for purposes of a reasonable accommodation under the ADA," said Gerald L. Maatman Jr., chair of the global employment law practice at the Chicago law firm of Baker & McKenzie.

Such an interpretation is "decidedly employer-friendly," Mr. Maatman said.

"The ruling also has a practical side which allows workers to overcome this presumption if the facts demonstrate that the employer has made other exceptions to the provisions of the seniority system; thus, it won't eliminate litigation in this area for employers entirely," he said.

"The `facts and circumstances' test crafted in Barnett may well embolden plaintiffs lawyers in the right case to get past summary judgment and impose trial costs and risks on employers in denial of reasonable accommodation cases brought under the ADA," Mr. Maatman said.

"It's not an out-and-out victory. The court is dancing on the head of a pin. They're trying to satisfy everybody and, as a result, satisfied no one," said Philip M. Berkowitz, chairman of the American Bar Assn.'s Employment Law Committee's International Law Section.

"They recognized that a bona fide seniority system should have primacy in reaching the difficult decision of whether an employee should get a job, notwithstanding a seniority system," said Mr. Berkowitz, who is also partner in the employment law department in the New York office of the international law firm of Salans Hertzfeld Heilbronn Christy & Viener.

But if an employee can show that the seniority system is not "fulfilling the purpose of a seniority system"-which, according to the Supreme Court, is to provide stability and fair and uniform treatment-the employee may be able to make a case, Mr. Berkowitz said.

"This is where it's a mixed result. Employers need to be very careful that they administer their seniority systems in a way that is consistent, that they don't make exceptions for people and that it's not a willy-nilly process," he said.

If the seniority system has not been consistently administered, then the employee will be able to argue that the employer can make a reasonable accommodation, Mr. Berkowitz said. He predicted that the decision will lead to a tremendous amount of discovery in such litigation, as plaintiffs attempt to find inconsistencies in their employers' application of seniority.

Steven Bokat, executive vp of the National Chamber Litigation Center in Washington, which handles litigation for the U.S. Chamber of Commerce, viewed the decision with greater optimism, calling it a "positive development" for business.

"In most cases, employers will be able to follow their seniority plans without worrying about ADA obligations. Employees can demonstrate that there are justifications for ignoring the seniority plan, but I think it's going to be a tough burden to meet," Mr. Bokat said.

An advocate for disabled workers had a different view of the decision.

"It didn't completely shut the door," said Jeffrey T. Rosen, general counsel and director of policy for the National Council on Disability, an independent federal agency. "This leaves a little bit of an opening for people with disabilities who are able to argue that there are special circumstances."

Mr. Rosen said that the high court will have to "sort things out" regarding the rights of the disabled, much as it has in other areas of civil rights law.

Meanwhile, in a case of interest to insurers and policyholders in California, the justices refused last Monday to review a California appellate court ruling in 20th Century Insurance Co. vs. Superior Court of California. That decision upheld a state law extending the period for refiling claims stemming from the 1994 Northridge earthquake.

US Airways vs. Robert Barnett, U.S. Supreme Court, No. 00-1250. Decided April 29, 2002.