In what could become a political hot potato, the fate of South African poet Dennis Brutus now lies in the hands of the Reagan administration.
Last week the black writer, an outspoken critic of South Africa's complex system of racial segregation who has been exiled in the United States for more than 10 years, filed for political asylum with a federal immigration judge in Chicago.
The petition will be taken up by the US State Department and, for the Reagan administration, it could spotlight anew the sensitive US-South Africa relationship.
Mr. Brutus's petition is the latest in a long line of legal moves between the exiled poet and the US Immigration and Naturalization Service.
A 10-year resident of the US and a tenured professor at Northwestern University in Evanston, Ill., Brutus has attracted national attention with his efforts to remain in this country.
Ruled ''deportable'' by a Chicago immigration judge last November, Brutus and his supporters have strenuously fought his possible deportation to Africa. Citing his ''distinguished scholar status,'' they contend that his recent immigration infractions -- working in the US without a valid passport and work permit -- were beyond his control.
Brutus was born in Rhodesia, now Zimbabwe, although he was raised in South Africa. When Zimbabwe gained independence from Britain last year, all British passports were withdrawn and Rhodesian citizens, of whom Brutus was one, were told to reapply for new passports from Zimbabwe. He was caught working in the US without a valid passport before he got his new passport. Thus he was unable to renew his US visa and work permit in time.
Such an infraction of US immigration law is usually remedied by leaving the country and simply reapplying for admission. But Brutus, who maintains he is not seeking US citizenship, and his supporters object to this solution on two grounds: no assurance has been given the poet that he will be allowed to reenter the US; and they see a likelihood that the poet would become a target for harassment and possible assassination by the South African secret police.
His Chicago-based attorney, Nasif Mahmoud, says the ''best legal strategy'' now is filing for political asylum. Not only does this move halt all deportation procedings, but it forces the State Department to rule on the case's individual merits and not simply on the basis of immigration law.
Such a move is what Dennis Brutus's supporters want. Dennis Brutus Defense Committees have sprung up in academic communities across the country. Other supporters, including Sen. Paul Tsongas (D) of Massassachusetts, the Congressional Black Caucus, and the president of Amherst College, where the poet is a visiting professor this year, have stepped forward to lobby for his defense.
They contend that should the poet be forced out of the US, even to such countries as Britain or Canada, he could become a target for possible assassination by the South African secret police. He has already been shot once and imprisoned several times by police in South Africa. Incarceration is automatic if he returns to South Africa, which he calls his homeland.
While it may be difficult to accurately assess the danger, supporters point to several incidents as telling:
* His continued protests against South Africa while living in the US. Considered a ''good organizer against apartheid,'' no matter where he is, Brutus has lobbied against Northwestern University's multimillion dollar holdings in South Africa, and this year was one of the first to protest the touring South African Springbok rugby team.
* The recent British publication of a book entitled ''Inside BOSS'' which is about the South African secret police. In one chapter, Brutus is described as a man considered by the South African government to be one of its most dangerous opponents.
* The murder in Salisbury, Zimbabwe, last July of former nationalist guerrilla leader, Joe Gqabi, with whom Brutus had been imprisoned some years earlier in South Africa. Zimbabwe Prime Minister Robert Mugabe has accused South Africa of the assassination.
Thus far, the State Department has made no comment on the situation, not even to confirm that the controversial writer has even filed for political asylum. But John Brahos, the chief legal officer for the Chicago immigration district, who has handled the situation thus far, maintains that -Brutus's case is ''not unusual.''
''We have only ruled that he is deportable,'' says Mr. Brahos, ''we have made no moves to actually deport him.''