ASHINGTON, April 26 - The Supreme Court on Tuesday curbed the reach of a federal law that prohibits convicted felons from possessing guns, ruling 5 to 3 that the law does not apply to those who were convicted by courts in foreign countries.

The majority arrived at that conclusion by interpreting the statute's reference to a conviction in "any court" to mean "any court in the United States." Justice Stephen G. Breyer's majority opinion said that in the absence of any indication that Congress even considered the issue when it enacted the law in 1968, the court should apply a legal presumption that "Congress ordinarily intends its statutes to have domestic, not extraterritorial, application."

Justice Breyer said the gun law would create anomalies if applied to foreign convictions, because foreign legal systems have made different choices of what conduct to regard as criminal. Citing the Russian criminal code as an example, he said that someone might be regarded as a felon "for engaging in economic conduct that our society might encourage." A foreign conviction does not necessarily indicate that a person is dangerous, Justice Breyer said.

The law, often referred to as the felon-in-possession statute, makes it illegal for someone "who has been convicted in any court of a crime punishable by imprisonment for a term exceeding one year" to possess a firearm. Because it imposes mandatory sentences on the basis of a record of previous convictions, prosecutors commonly add a felon-in-possession charge when seeking an indictment for other offenses.

In this case, Small v. United States, No. 03-750, the gun possession itself was the offense. Gary Small, who had been convicted in Japan of smuggling guns into that country and served three years in a Japanese prison, bought a gun within a week of returning to the United States.

Mr. Small pleaded guilty to a gun possession charge, while reserving the right to appeal on the ground that the felon-in-possession statute did not apply to his Japanese conviction. The United States Court of Appeals for the Third Circuit, in Philadelphia, rejected his argument in a 2003 decision that the Supreme Court overturned on Tuesday.

Dissenting, Justice Clarence Thomas said the majority had stretched to create an exception that the law itself did not provide. "In concluding that 'any' means not what it says, but rather 'a subset of any,' the court distorts the plain meaning of the statute," Justice Thomas said.

He also objected to the majority's assumption that application of the law to Mr. Small would give it an "extraterritorial" dimension.

"The statute criminalizes gun possession in this country, not abroad," he said. "In prosecuting Small, the government is enforcing a domestic criminal statute to punish domestic criminal conduct."

Justices Antonin Scalia and Anthony M. Kennedy joined the dissenting opinion. Justices John Paul Stevens, Sandra Day O'Connor, David H. Souter and Ruth Bader Ginsburg joined the majority. Chief Justice William H. Rehnquist, who had just begun treatment for thyroid cancer when the case was argued on Nov. 3, did not participate.

The case was the court's latest of several efforts to interpret federal gun laws in which simple language masks layers of legal complexity. In 1995, for example, the court examined a federal law that makes it a crime to "use" a gun in connection with a narcotics offense, and decided that "use" meant "active employment" of the gun rather than keeping it locked in a car trunk.

In the new case, the majority said that to discern the meaning of "any" in the statute, "we must look beyond that word itself" to the way the word would ordinarily be used. In announcing the decision from the bench, Justice Breyer gave an example. If he offered to see a particular movie at "any theater," he said, "I'm not talking about theaters in Japan."

A second case on Tuesday involved "any" in a different statute, the federal wire fraud law, which makes it a crime to use interstate wires to carry out "any" scheme to defraud.

The question was whether the law applied to a smuggling operation intended to evade Canada's high liquor taxes by hiding liquor in trucks and driving them across the border from New York. The operation involved telephoning orders from New York to discount liquor stores in Maryland. The government's theory was that the scheme defrauded Canada of its rightful tax revenue.

The three defendants, David and Carl Pasquantino and Arthur Hilts, argued both before trial and after their convictions that a legal doctrine known as the revenue rule meant that the wire fraud law could not apply to their case. Under this rule, one government cannot use the courts of another to collect taxes.

But the rule does not apply in this case, Justice Thomas wrote in a majority opinion affirming a ruling by the United States Court of Appeals for the Fourth Circuit, in Richmond, Va., which had upheld the men's convictions. "This is a criminal prosecution brought by the United States in its sovereign capacity to punish domestic criminal conduct," he said.

The vote in this case, Pasquantino v. United States, No. 03-725, was 5 to 4, with Justices Ginsburg, Breyer, Scalia and Souter dissenting. "The court has ascribed an exorbitant scope to the wire fraud statute" in giving it "an extraordinary extraterritorial effect," Justice Ginsburg said in her dissenting opinion.

Justice Thomas replied in his majority opinion that neither the government's use of the statute nor the court's interpretation of it gave it an extraterritorial effect. The defendants' "offense was complete the moment they executed the scheme inside the United States," he said.

At the end of his opinion, Justice Thomas observed that "it may seem an odd use of the federal government's resources to prosecute a U.S. citizen for smuggling cheap liquor into Canada." But the "broad language of the statute" permitted the prosecution, he said.