Anti-apartheid poet-activist Dennis Brutus was granted political asylum in the United States today by a crusty immigration judge who said Brutus' life would be in danger if he were forced to return to his native Zimbabwe.

Judge Irving Schwarz agreed with almost every point of Brutus' defense against the deportation order the federal Immigration and Naturalization Service (INS) first brought against him almost three years ago. Brutus' lawyers had contended his life was in danger from South African security forces who might seek him out because of his vocal opposition to Pretoria's race laws.

Brutus, 58, a tenured professor of English at Northwestern University in Evanston, Ill., called the judge's decision "a political victory in the fight against racism." INS Chief Legal Officer Samuel Der-Yeghiayan said the service reserves the right to appeal the decision. The judge's ruling otherwise seems to bring to an end Brutus' complicated immigration troubles. INS has 10 days to appeal.

Schwarz, an older man with gray hair and a feisty courtroom manner, had remarked at a lunch break here at the federal courthouse that he expected it would take up to a month of review to decide the case.

Instead, about an hour after the deportation hearing resumed in the afternoon, he announced his verdict: "He [Brutus] has made himself hated by just about every [white] South African for his views and actions on sports. He has made himself a prime target . . . There is no question that Professor Brutus poses a threat to the government of South Africa."

During the past 20 years Brutus has been in the forefront of the effort to ostracize South Africa from international sports competitions because of its discriminatory race laws, which deny fundamental freedoms to the majority 25 million black, mixed and Oriental subjects. Since 1964, South African teams have been barred from the Olympics and other major international sports events, in part because of his efforts.

Schwarz said the evidence presented by Brutus' lawyers at a week-long hearing earlier this summer showed that South Africa "clearly" seeks out its enemies and mobilizes squads that "go in and commit mayhem or murder or even kidnaping."

During the earlier hearing several witnesses for Brutus testified that they believed his safety was in jeopardy if he were to return to Zimbabwe.

Brutus was born there in 1924 but spent most of his life in South Africa. Beginning in the 1950s he became active in opposing the race laws. In South Africa, Brutus is classified as a "colored" of mixed racial descent. In the 1960s he was arrested, tortured, shot and imprisoned on Robben Island, the escape-proof concentration camp for political prisoners off the South African coast.

He was forced into foreign exile in 1966 and lived in London for four years before immigrating here in 1970 at the invitation of Northwestern. He has remained here on a series of temporary visas. But in 1980, when Southern Rhodesia became the new nation of Zimbabwe, his citizenship status grew cloudy.

While waiting for a new Zimbabwe passport to arrive, he missed deadlines imposed by INS for renewal of his temporary visa. Some months later, immigration officials instituted deportation proceedings, on the grounds that they had reason to believe Brutus had no intention of living anywhere else but the United States.

During today's hearing INS lawyers sought to show that Brutus had a permanent residence in London and therefore implied he could safely return there if expelled from this country. But Schwarz in his verdict concluded that Brutus had never established a permanent London residence.

Applause broke out in the courtroom full of about 40 Brutus supporters as Schwarz delivered his extemporaneous remarks.