The Supreme Court, in a major victory for the press, made it easier yesterday for the news media to win dismissal of libel suits without costly trials.

The 6-to-3 ruling reversed a 1984 decision by President Reagan's nominee for the court, appeals Judge Antonin Scalia, in a case involving columnist Jack Anderson and the conservative Liberty Lobby. A magazine edited by Anderson had said the group and its founder, Willis Carto, were neo-Nazi, anti-Semitic, racist and fascist.

The opinion by Justice Byron R. White said judges should carefully consider whether public figure libel plaintiffs have presented sufficient evidence to justify a jury trial and should dismiss cases where evidence of "actual malice" by the media is not "clear and convincing."

The ruling resolves seven years of confusion over the legal standards trial judges should use in deciding whether to send a libel case to a jury.

Lawyers on both sides said yesterday's ruling will mean that far fewer libel suits, especially those brought by public figures, will end up before a jury. It could save the news media millions of dollars in litigation costs.

The trial judge in the Anderson case dismissed it before trial, ruling that Carto failed to present enough evidence to justify letting a jury consider whether the magazine had published the article with actual malice, that is, knowing it was false or with reckless disregard for whether it was false.

Such pretrial dismissals by judges had been routine until a high court ruling written by Chief Justice Warren E. Burger in 1979 in Hutchinson v. Proxmire. A now celebrated footnote in that opinion had been interpreted by many judges to mean that the high court did not favor pretrial dismissals in cases involving public figures.

The footnote said public figure cases require probing a writer's "state of mind" to prove that a falsehood was published with "actual malice." "Such a case does not lend itself to summary pretrial disposition," the footnote said.

Media lawyers contended that the footnote resulted in numerous meritless libel cases going to trial.

Citing that footnote, Scalia had said the judge erred in throwing out the lawsuit against The Investigator, a magazine edited by Anderson. Scalia said the judge, who used the legal standard required in libel cases by the high court's landmark decision, New York Times v. Sullivan, wrongly dismissed some of the allegations.

"Imposing the increased proof requirement at this stage before trial ," Scalia said, "would effectively force the plaintiff to try his entire case" first before the judge and then before a jury. Scalia, saying plaintiffs should not be held to such a high standard of proof, ordered the case to go to trial.

White reversed that ruling yesterday in Anderson v. Liberty Lobby. A court ruling on a motion for summary judgment must be guided by the stringent New York Times "clear and convincing" standard.

White said the standard "provides that the mere existence of some alleged factual dispute between the parties" on the issue of malice is not enough to send the case to a jury. The disputed facts must be significant enough to affect the outcome of the trial, he said.

David J. Branson, Anderson's attorney, hailed yesterday's ruling, saying it "buried" the troublesome footnote in the 1979 case.

Media attorney Bruce Sanford said the ruling will have an "enormous practical dollars and cents impact" and that it "sends a broad clear message to all trial judges to dispose of all weak or meritless cases prior to trial."

Plaintiffs attorney Michael P. MacDonald also predicted the case will have an "enormous impact" and will "drastically reduce the constitutional right of a libel litigant to a jury trial."

Justice William J. Brennan Jr., in a strong dissent, said the majority's analysis was "deeply flawed" and that the decision changed legal procedures not just for libel cases, giving judges increased discretion and making it more difficult for litigants in any type of case to get their claims heard by a jury.

Justice William H. Rehnquist, joined by Burger, also dissented, saying the majority opinion "will do great mischief with little corresponding benefit."