The Supreme Court yesterday considered whether people convicted of a crime overseas can be barred from owning a gun in the United States, with the argument at times centering on how the absent Chief Justice William H. Rehnquist might rule.

On a day when Democratic Sen. John F. Kerry's concession to President Bush ended the presidential campaign without legal challenges to the outcome, the eight justices went about their business of hearing arguments and bantered at times. Rehnquist missed a third day of arguments; he disclosed Monday that he is undergoing radiation and chemotherapy for thyroid cancer, news that has prompted intense speculation about whether he will retire.

U.S. law forbids felons from owning guns, with a few exceptions for antitrust and trade violations. At issue is whether Congress meant to include foreign convictions when it criminalized firearm possession by anyone convicted in "any court."

"I'm going to ask a question the chief justice would ask if he were here, because he always asked it," Justice Antonin Scalia said. "If you had to pick your best case in interpreting the word 'any,' what would it be?"

Government attorney Patricia Millett responded that the Supreme Court had always given the word "any" a broad meaning to help promote gun safety, before Justice Ruth Bader Ginsburg jumped in, citing a decision Rehnquist wrote that she said suggested otherwise.

"When Congress legislates, it usually is thinking only about the United States," she said, contending that lawmakers never contemplated foreign convictions. "The chief made the point."

Rehnquist has reserved the right to rule on cases heard this week based on the written briefs and transcripts of the oral argument. Some Supreme Court observers have said Bush's reelection might speed the conservative chief justice's decision to retire after 32 years on the court.

The case heard yesterday involves Gary Sherwood Small of Pennsylvania, who answered "no" to a felony conviction question on a federal form when he bought a handgun in 1998, though he had been convicted of violating weapons laws in Japan.

Small was indicted in 2000 on charges of lying on the form and illegally owning two pistols and 335 rounds of ammunition. He later entered a conditional guilty plea pending the outcome of the Supreme Court ruling.

Small's attorney, Paul D. Boas, argued yesterday that the gun law should not apply to foreign crimes, noting that other sections in the statute referred only to U.S. convictions when it created the exceptions for antitrust and trade violations.

"We can't ignore the entire statutory scheme here, which time and time again refers to domestic matters," Boas said.

To Scalia's question what the best case would be that Rehnquist would want to know about, Boas said he would have to think. "He asked a good question," Boas commented jokingly.

The case is Small v. United States, 03-750. A ruling is expected by July.