THE PERSONAL and political history of Edgar Chamorro Coronel makes him more than an unusually intriguing immigration case. Chamorro, a member of the most powerful clan in Nicaragua and one-time darling of the CIA, broke with the contras in November 1984, and is now threatened with deportation from the United States.

A former Jesuit priest, who was extensively educated in this country, Chamorro was in Washington last month, vigorously lobbying against "humanitarian" aid to the contras, and sympathizers in Congress are crying that his threatened expulsion is "politically inspired" (Rep. Bill Alexander, D-Ark.) and a "perfect example of the administration using the immigration laws to censor debate" (Rep. Barney Frank, D-Mass.).

Perry A. Rivkind, district director of the Immigration and Naturalization Service (INS) in Miami, says he knows "how it looks," but denies that there is any vindictiveness in the "routine processing" of Chamorro's 1980 request for political asylum. "I never met Chamorro and, until this happened, I didn't know anything about him," he says.

He says that two recent Chamorro articles in U.S. newspapers which were highly critical of U.S. policy in Nicaragua "rang a bell" and caused him to look up Chamorro's file. His petition for asylum was turned down "just like 90 percent of requests from that area" long before Chamorro turned on the contras.

The matter has stirred up passions in Miami, with pro- Sandinistas threatening to picket the INS office and pro-contras being exhorted by a fiercely anticommunist local paper, La Cubanissimo, to demonstrate outside Chamorro's house.

Chamorro thinks the INS action could be a "coincidence," that bureaucratic delays and confusion with a cousin by the same name could have caused the problem. But it may be academic anyway, because, according to Chamorro's lawyer, Grisel Ibarra, Chamorro's sister applied for his admission under the "fifth preference" section of the INS code in l980, and her petition could be taken up before lengthy deportation proceedings even get under way.

The INS appears slightly embarrassed by another instance of the zeal which caused the exclusion of Hortensia Allende, widow of Salvador Allende of Chile. Much skepticism attends its version of events, because Reagan has never shown in dealing with Nicaragua the restraint that marked his recent performance on Beirut.

Chamorro says he was totally sympathetic to the revolution but dubious about the Sandinista government from the first.

"Too much Castro," he said on recent trip to Washington. "Daniel Ortega grew up in a house with Fidel's picture on the wall -- his father greatly admired him. That's the trouble with Latin America -- no role models."

In 1979, Chamorro brought his wife and children to Miami to watch from afar how the wind would blow. A quick trip later that year to Costa Rica with forays across the border for meetings with old friends in power convinced him that the direction was hopelessly Marxist-Leninist, and he came back to the United States to stay. His house in Managua was confiscated by Tomas Borge, the minister of defense.

By 1982, he was persuaded that only sharp, quick military action could rescue his country from the "tyrannical" Sandinistas, and he was recruited by the CIA for the FDN, the contra group set up by the CIA. With his brains and connections, Chamorro was considered a catch. He was made a director, provided with false travel documents by the CIA and made countless trips back and forth to Honduras and Costa Rica. A CIA agent arranged a "final" interview with the INS for his political asylum petition.

But he soon became disillusioned. Late in 1984, in an interview with Christopher Dickey of The Washington Post, he criticized the "cold-blooded executions" carried out by ex-Somocistas who think that "to kill a communist is not really killing" and the total CIA control of the contras.

Chamorro was fired by contra leader Adolfo Rubelo. He is now urging a political solution to the problem.

"I would like to go back to Nicaragua one day," he says. "But I don't want to be deported. If I go to Costa Rica, which is where the INS wants me to go -- they think I lived there and they've got me mixed up with a cousin with the same name -- the contras would come and kill me. If I went to Nicaragua, I would be used by the Sandinistas, as a defector from the contras. Or they could try me. The amnesty declaration on contras doesn't cover the leaders."

Chamorro thinks the contras are on the wrong track because they want to replace the current group with a "good Somoza."

"What we need is not strong men but strong institutions," he says.

The prospects are currently remote. It is not easy for someone who believes in genuine democracy to live in Nicaragua -- or, for that matter, the United States.