The core of the Justice Department's case against Archbishop Trifa was that he had entered the United States under false pretenses in 1950. It charged that he concealed a past that included membership in a group called the Iron Guard, a fascist movement that was the Rumanian parallel of the Nazi storm troopers in Germany.

Federal officials said a speech in Bucharest by Archbishop Trifa on Jan. 20, 1941, touched off four days of attacks in which 300 Jews and others were killed.

Archbishop Trifa repeatedly denied that he directed an attack against Jews. But he acknowledged, when faced with evidence, including a picture of him in the uniform of the Iron Guard, that he was a member of the group. He also admitted to editing an anti-Jewish newspaper and giving pro-Nazi speeches.

He remained unrepentant. ''I am not ashamed of my past at all,'' he said to an interviewer in 1973. ''For those circumstances in that time I think that I didn't have any other alternative but to do what I thought to be right for the interests of the Rumanian people.'' Calls Speeches Standard

When shown texts of speeches bearing his name, the Archbishop said they were standard oratory for student leaders all over Rumania. ''I didn't write my own speeches,'' he said.