The Supreme Court yesterday let stand a federal ban on the sale of new fully automatic machine guns, declining to consider arguments by the National Rifle Association and other pro-gun advocates that the prohibition is an unconstitutional infringement on the right to keep and bear arms.

The action in Farmer v. Higgins was quickly hailed by a leading gun control group as "the worst legal defeat ever suffered by the NRA." But a NRA official said the court's decision not to hear a challenge to the 1986 Firearms Owners Protection Act was an "extraordinarily narrow" action that had no effect on the constitutional rights of gun owners.

The challenge to the machine gun ban had become a lightning rod for advocates on both sides of the gun control issue in recent weeks, with police groups and others condemning the NRA's arguments that the restriction violated the Second Amendment.

Responding to the concerns of law enforcement groups, Congress in 1986 prohibited the sale or purchase of machine guns -- a restriction the NRA criticized as the "first ban on firearms possession by law-abiding citizens in American history." Private individuals who registered their guns and underwent background checks can still possess machine guns purchased before 1986.

Barbara Lautman, executive director of the Center to Prevent Handgun Violence, said the group was "delighted the court decided not to dignify" the NRA's arguments. "This once again frees up people to debate the gun issue on its merits rather than as something that has anything to do with constitutionally guaranteed freedoms," she said.

A Georgia gun maker, J.D. Farmer Jr., challenged the 1986 law by suing the head of the Bureau of Alcohol, Tobacco and Firearms, Stephen E. Higgins. A federal judge ruled in January 1989 that the bureau had improperly interpreted the ban in denying Farmer a license to manufacture a new machine gun. A federal appeals court overturned that ruling and rejected Farmer's argument that the law is unconstitutional.

John Lenzi, state liaison for the NRA, noted that the court's action has no impact on the approximately 100,000 citizens who lawfully own machine guns. "The denial. . . is in no way an indication of the court's support for a prohibition on firearms ownership nor is it a decision even remotely involving the Second Amendment," he added.

In other action yesterday, the court agreed to decide the constitutionality of a federal law that gives the attorney general emergency power to classify drugs as illegal substances.

The court said it would hear a New Jersey couple's challenge to their convictions for manufacturing an amphetamine-like stimulant called "Euphoria."

Congress in 1984 gave the attorney general broad emergency power to act to criminalize the manufacture and sale of so-called "designer drugs" if he finds it "necessary to avoid an imminent hazard to the public safety." That action, which can last for as long as 18 months, can take place without the procedural steps required for a permanent classification and without the opportunity for court review.

The couple, Daniel and Lyrissa Touby of Fairlawn, N.J., argued that Congress in passing the law delegated too much of its power to the attorney general, who in turn gave that authority to the head of the Drug Enforcement Administration.

The court also said it would decide whether a provision of the California constitution violates the First Amendment in prohibiting political parties from endorsing candidates for judgeships and local offices.

Trying to avoid political corruption and reduce the domination of party machines, California since 1913 has conducted city, county, school board and judicial elections on a nonpartisan basis, meaning that candidates' party affiliations are not listed on the ballot. In 1986, state voters approved a constitutional amendment to prohibit party endorsements as well.

A group of political activists in San Francisco challenged the ban as a violation of freedom of speech, and the federal appeals court in San Francisco, splitting 8 to 3, agreed.

In asking the high court to hear the case, Renne v. Geary, San Francisco argued that the appeals court failed to give enough weight to the state's interest in assuring the independence of local officials and judges. "Without an endorsement ban, the danger of making judges and local officials beholden to political parties will remain," the city argued.

The city was supported by the California Judges Association.