ASHINGTON, April 23 — The Supreme Court appeared poised today to overturn California's Holocaust Victim Insurance Relief Act, which requires insurance companies doing business in the state to disclose information about every policy that they or their affiliates sold in Europe from 1920 through 1945.

"What we have here is a state trying to establish its own foreign policy," Deputy Solicitor General Edwin S. Kneedler told the justices, arguing that the troublesome issue of recovering insurance benefits to which Holocaust survivors are entitled was "exclusively a matter for the national government."

The justices, who three years ago unanimously overturned a Massachusetts law establishing a state boycott of companies doing business in Myanmar, the former Burma, seemed at times almost impatient with California's defense of its effort to make Holocaust-era disclosure a condition of a business license.

"This law makes reference to Nazi-controlled Germany and the Holocaust, none of which is California's concern," Justice Anthony M. Kennedy told Frank Kaplan, representing the California insurance commissioner.

Justice Stephen G. Breyer said, "The problem is that the Constitution seems to give authority to the secretary of state and not to the insurance commissioner of California" to address the insurance issue.

Mr. Kaplan said the law represented the state's effort, on behalf of as many as 20,000 Holocaust survivors in California, to "address the stone-walling that has gone on for years and that continues to this day" on the part of insurance companies that have withheld information from family members seeking to collect on policies.

The California law, enacted in 1999, was challenged immediately by the American Insurance Association and by 10 insurance companies, including those with origins or affiliates in Germany, Switzerland and Italy. The Federal District Court in Sacramento declared the law unconstitutional in 2000, and the United States Court of Appeals for the Ninth Circuit, in San Francisco, overturned that decision last year.

The statute authorizes suits against the insurance companies in the California courts. Only the disclosure provision, not the law's remedial aspects, were before the court today in American Insurance Association v. Garamendi, No. 02-722.

In their arguments, both Mr. Kneedler, the deputy solicitor general, and Kenneth S. Geller, representing the insurance companies, emphasized the recent history of executive branch involvement in negotiating solutions to Holocaust-era claims. A group called the International Commission on Holocaust Era Insurance Claims, set up by a group of European insurance companies and Jewish organizations, is processing claims it receives from individuals after checking their names against a database it is compiling. Under an executive agreement between the United States and Germany, all claims against German insurance companies are being submitted to this commission.

Both Mr. Geller and Mr. Kneedler emphasized that the process respected the privacy laws of European countries by disclosing insurance information only when sought by identified Holocaust victims and families. By contrast, the California law requires disclosure of some 10 million policies issued during the time period, fewer than 1 percent of which were owned by Holocaust victims.

Justice Ruth Bader Ginsburg appeared unimpressed with the privacy argument. "We are dealing with a unique situation here," she said, noting that many of the policy-holders were killed. "To raise the privacy interest with respect to these people is kind of ironic," she said.

Justice Ginsburg observed to Mr. Kneedler that California was simply "asking questions of companies licensed to do business in California."

Mr. Kneedler replied, "Disclosure is a form of regulation" and he added that "states don't have the right to regulate through disclosure transactions that occurred outside the state."

Defending the law, Mr. Kaplan invoked the court's recent solicitude for states' rights, noting that Congress has long authorized the states to regulate insurance and has said nothing to pre-empt the California law or others like it. "Congress didn't say stop," he said.

But the states'-rights argument made little headway. Justice Sandra Day O'Connor observed that insurance companies could lose their California licenses under the law for failing to disclose information that European privacy laws might not even make available. "What kind of a law is that?" she demanded.

Representative Mark Foley, Republican of Florida, said today that he would introduce a bill next week to make clear that states have the authority to require disclosure of Holocaust-era insurance policies and to permit suits in federal court.