When Joe Doherty broke out of a maximum security prison in Northern Ireland seven years ago, the Irish Republican Army's underground network of safe-houses and sympathizers led him to this working-class, Irish-American suburb of New York City.

Doherty had been convicted with three others of killing a British army officer in a 1980 shootout.In Kearny, he lived with an American girlfriend, worked in construction and took a part-time job at Clancy's Bar in Manhattan.

"It was sort of like being normal for once . . . having a job and knowing you're not going to get assassinated or stopped in the streets because of your religion," Doherty said in a recent interview at the Metropolitan Correctional Center in Manhattan.

On June 28, 1983, a group of FBI agents walked into Clancy's, ordered a round of beers and took him into custody again.

Since then, the case has grown to involve the White House, the Justice Department, civil rights activists and the leaders of Great Britain and Ireland.

Doherty doesn't deny being involved in the killing but says it was a political act and that he warrants political asylum in the United States.

The government disagrees. The Justice Department calls Doherty a terrorist and says he should be deported to Britain.

"The question of who gets political asylum and who is a refugee should be based on the law, on facts and on circumstances," said Mary Pike, Doherty's lawyer. "But the question really depends on which government you're fleeing. If it's a government with which the Reagan administration wants to remain friendly, then you can't get asylum."

"If I was a Cuban," said Doherty, "there's no way I would be deported."

Doherty, a bachelor, has spent the better part of his 33 years in hiding or in prison. He joined the IRA in 1969 after the British army crushed a Catholic civil rights march on what has become known as Bloody Sunday.

"I'd watched my father live his life as a second-class citizen and tell me to learn a trade and then emigrate," said Doherty. "I didn't want to tell my son at 17 that he had to go to Canada to find a job because of his religion."

While lawyers debate his case, Doherty has spent the past five years in a 12-foot-by-6-foot cell at the federal prison in New York.

"I see this case as a complete rejection of the Constitution by the government," said Paul O'Dwyer, a civil rights attorney in New York. "There is no other prisoner I know of who has been held for such a protracted period of time having committed no crime in the United States."

Tom Moseley, a former Justice Department attorney who handled the Doherty case, said the bottom line is that Doherty is a terrorist who killed someone.

"We felt he should have been extradited to the U.K. on the grounds of murder and assault," said Moseley, now in private practice in Morristown.

Some who sympathize with the IRA's goal of uniting the Republic of Ireland with the northern six counties that make up the British province of Northern Ireland consider Doherty a folk hero.

The Justice Department went to court last year to stop Philadelphians from naming Doherty honorary grand marshal of their St. Patrick's Day parade.

"Free Joe Doherty" graffiti adorns walls and sidewalks all over New York City. At a New Jersey bar not far from where Doherty lived, his picture hangs alongside that of Bobby Sands, the IRA prisoner who starved to death during a 1981 hunger strike at a British prison.

Among Doherty's supporters are New York's Roman Catholic Archbishop Cardinal John O'Connor, Amnesty International, the American Civil Liberties Union and the Rev. Jesse Jackson, who visited Doherty in prison in July.

But there also are influential forces fighting for Doherty's extradition.

British Prime Minister Margaret Thatcher raised the case in talks with President Reagan during a 1986 visit to Washington.

Sen. Richard Lugar, R-Ind., described the jailed IRA man as "an Irish Ghengis Khan." Lugar led a successful fight to exclude the political exception clause from the century-old U.S.-British extradition treaty when it was renegotiated in 1986.

The British government filed a formal request for Doherty's extradition in 1983. It was denied in December 1984 by U.S. District Judge John E. Sprizzo in Brooklyn, who ruled that Doherty's crime was a political act and qualified the defendant for political asylum.

The government appealed and U.S. District Judge Charles S. Haight decided in Doherty's favor. A government appeal to the U.S. Court of Appeals in New York upheld Doherty's previous victories.

Having failed to extradite Doherty, the Justice Department began deportation proceedings.

Since the law says deportees can choose where they are sent, Doherty chose the independent Republic of Ireland and his decision was upheld by immigration Judge Howard I. Cohen in 1986.

But the Republic of Ireland, under pressure from London and Washington, in December 1987 ratified the European Convention on Terrorism, which calls for mandatory extradition of those deemed terrorists. That eliminated Doherty's Irish option.

Today, Doherty is pinning his hopes on winning asylum.