The U.S. Supreme Court declared yesterday that a federal law prohibiting demonstrations on the sidewalks around its own building was an unconstitutional violation of First Amendment protections of free speech.

But the narrow ruling applied only to the sidewalk area, not to the plaza or steps in front of the building, and it overturned a 1981 U.S. Court of Appeals ruling that would have opened those areas as well to demonstrators.

Justice Byron R. White, writing for seven justices, said the sidewalks around the court are "indistinguishable from any other sidewalks in Washington, D.C., and we can discern no reason why they should be treated any differently."

Peaceful picketing or leafleting, White said, are protected activities under the First Amendment and must be allowed on the court's sidewalks.

But White said that while the public can freely enter and leave the court grounds at virtually anytime, that does not "transform" the court grounds into a "public forum" area--such as the streets, sidewalks or parks--where the government's right to restrict demonstrators is "very limited."

In a partial dissent, Justice Thurgood Marshall said that he would have upheld the three-judge appellate court panel and overturned the law itself. Marshall said the court was a public place much like any other.

"I would not leave visitors to this court subject to the continuing threat of imprisonment if they dare to exercise their First Amendment rights once inside the sidewalks," Marshall said, adding in a footnote that the statute carries a penalty of 60 days in jail or a $100 fine or both.

Yesterday's ruling came in a case involving a woman who stood in front of the court with a sign on which she had printed verbatim the First Amendment, and an elderly Catholic missionary who distributed leaflets on three occasions in 1978 and 1980 on the sidewalk in front of the court.

Assistant U.S. Attorney Royce C. Lamberth, who advises local chiefs of police on matters involving demonstrations, said the decision means that demonstrators in front of the court would still be subject to a D.C. law that prohibits blocking public sidewalks.

The U.S. High Court Backs Free Speech on Its Sidewalks By Al Kamen Washington Post Staff Writer

The U.S. Supreme Court declared yesterday that a federal law prohibiting demonstrations on the sidewalks around its own building was an unconstitutional violation of First Amendment protections of free speech.

But the narrow ruling applied only to the sidewalk area, not to the plaza or steps in front of the building, and it overturned a 1981 U.S. Court of Appeals ruling that would have opened those areas as well to demonstrators.

Justice Byron R. White, writing for seven justices, said the sidewalks around the court are "indistinguishable from any other sidewalks in Washington, D.C., and we can discern no reason why they should be treated any differently."

Peaceful picketing or leafleting, White said, are protected activities under the First Amendment and must be allowed on the court's sidewalks.

But White said that while the public can freely enter and leave the court grounds at virtually anytime, that does not "transform" the court grounds into a "public forum" area--such as the streets, sidewalks or parks--where the government's right to restrict demonstrators is "very limited."

In a partial dissent, Justice Thurgood Marshall said that he would have upheld the three-judge appellate court panel and overturned the law itself. Marshall said the court was a public place much like any other.

"I would not leave visitors to this court subject to the continuing threat of imprisonment if they dare to exercise their First Amendment rights once inside the sidewalks," Marshall said, adding in a footnote that the statute carries a penalty of 60 days in jail or a $100 fine or both.

Yesterday's ruling came in a case involving a woman who stood in front of the court with a sign on which she had printed verbatim the First Amendment, and an elderly Catholic missionary who distributed leaflets on three occasions in 1978 and 1980 on the sidewalk in front of the court.

Assistant U.S. Attorney Royce C. Lamberth, who advises local chiefs of police on matters involving demonstrations, said the decision means that demonstrators in front of the court would still be subject to a D.C. law that prohibits blocking public sidewalks.

The opinion also appears to leave intact another federal statute that prohibits demonstrators in front of the court who are there with the intent of influencing the justices on pending cases, Lamberth said.

Such demonstrators probably will have to remain across the street on the Capitol grounds, where they are currently allowed to gather, provided they have a permit from Capitol Hill police, he said.

The ruling also does not affect regulations in effect since the late 1960s and early 1970s, when federal courts issued rulings in a series of cases involving antiwar demonstrators. Those rulings have, with some restrictions, upheld the rights of demonstrators to distribute leaflets and picket in areas such as the White House and Lafayette Square.

Groups of fewer than 25 persons who want to picket in front of the White House do not need permits, Lamberth said, but larger groups--generally up to a maximum of 750 in front of the White House and 3,000 in Lafayette Square--need to secure permits from the National Park Service.