The Supreme Court made it easier yesterday for persons to file libel suits - particularly those who appear on the public stage unwillingly.

In one ruiling, the court freed a man named Ilya Wolston of Arlington to seek damages as a result of being listed in a book "among Soviet agents identified in the United States."

In a second ruling, the court enabled scientist Roland R. Hutchinson to sue Sen. William Proxmire (D-Wis.), who had ridiculed his federally funded research as wasteful in awarding him a monthly "Golden Fleece."

The court decided both cases 8 to 1. The dissenter was Justice William J. Brennan Jr. In the Proxmire case, however, his objection related entirely to issues of congressional immunity.

In the book case and in one phase of the Proxmire case, the central libel issue was whether either Wolston, convicted long ago of criminal contempt, or Hutchinson was a private person or a "public figure."

Under previous court decisions, a private person may prevail by establishing defamation and a degree of fault on the part of the defamer - unless the defendants shows that the defamation was truthful.

By contrast, a public figure, under a line of ruling starting in 1964, carries a heavy burden: he must prove that a damaging falsehood was published "with 'actual malice' - that is, with knowledge that it was false or with reckless disregard of whether it was false or not."

Justice Harry A. Blackmun, while agreeing with the judgment that neither Wolston nor Hutchinson was a public figure, demurred in the Wolston case. The court seems to hold "that a person becomes a limited-issue public figure only if he literally or figuratively 'mounts a rostrum' to advocate a particulr view," Blackmun said.

Other reactions were mixed.

First Amendment expert Floyd Abrams said, "This decisions will necessarily limit what the public learns about real criminals, about possible wasters of public funds, and about others whose conduct, and possible misconduct, affect all of us."

The Reporters Committee for Freedom of the Press said the rulings will encourage the filing of "harassing" libel suits and deter publication of news on public events.

But Wolston's lawyer, Sidney Dickstein, foresaw "the salutary effect of causing the media to be somewhat more careful in how they deal with private citizens." At the same time, however, he said he does not foresee "the impact on free and fair reporting that some are claiming."

Justice William H. Rehnquist, writing for the court in the Wolston case, said the majority was refusing to "create an 'open season' for all who sought to defame persons convicted of a crime." And, he said, "A private individual is not automatically transformed into a public figure just by becoming involved in or associated with a matter that attracts public attention."

Born in Russia in 1918, Wolston lived in four European countries before coming to the United States in 1939. The Army drafted him in 1942 and honorably discharged him after he'd become a naturalized citizen, in 1946. He then worked as a governnment interpreter for several years.

The public-figure issue arose in 1957 and 1958, when his aunt and uncle, Myra and Jack Soble, pleaded guilty to being Soviet spies. Starting with the day of their arrest, he several times was interviewed by the FBI and summoned before a grand jury in New York City.

Finally, claiming mental depression, he tried to be excused from a grand jury appearance and, on July 1, 1958, disobeyed a subpoena to appear. When he was cited for contempt, his wife, called to testify about his mental condition, became hysterical on the witness stand.

Wolston then pled guilty. He drew a suspended sentence conditioned on future cooperation with the grand jury. These events were reported, over a six-week period, in 15 newspaper stories in Washington and New York. After that, Wolston - never indicted for espionage - returned to obscurity.

In 1974, Reader's Digest Association published - and two book clubs and a paperback house also issued - John Barron's "KGB: The Secret Work of Soviet Agents." In listing Wolston as an "identified" Soviet agent, Barron swore in an affidavit, he had relied, unquestioningly, on an FBI report.

Wolston sued. A trial judge, upheld by the U.S. Court of Appeals here, held that Wolston became a public figure by failing to appear before the grand jury and being convicted of contempt, and dismissed the suit summarily on the ground that Wolston couldn't prove "actual malice" motivated Barron. Justice Brennan, in dissenting yesterday, said the actual-malice issue should have gone to a jury.

For the appellate court, Judge Roger Robb wrote that "by his voluntary action, (Wolston) invited attention and comment in connection with the public questions involved in the question of espionage."

For the Supreme Court, Rehnquist - not dealing with the erosion of public-figure status by the passage of time - rejected Robb's classification of Wolston as "a limited-purpose public figure." Rather than getting into the spotlight voluntarily, he controversy," the justice wrote.

"Wedecline to hold that his mere citation for contempt rendered him a public figure for purposes of comment on the investigation of Soviet espionage," Rehnquist said.

"A libel defendant must show more than mere newsworthiness to justify application of the demanding" actual-malice standard, Rehnquist said. The court will not "create an 'open season' for all who sought to defame persons convicted of a crime," he emphasized.

Similarly, in the Proxmire case, Chief Justice Warren E. Burger wrote for the court that scientist Hutchinson did not become a public figure by responding to the senator's announcement that he had awarded a "Golden Fleece" to federal agencies funding Hutchinson's research.