The 11-year-old triple murder case involving former Green Beret doctor Jeffrey R. MacDonald was replayed yesterday in a fashion that made the setting seem more like a county courthouse than the U.S. Supreme Court.

Inside, the justices listened with unusual concentration to details ordinarily reserved for a jury as the government pleaded with them to reinstate MacDonald's conviction of the murders of his wife and two children. Outside, after the arguments, MacDonald pleaded his innocence to a crowd of reporters while his dead wife's father, still determined to avenge his daughter's murder, argued his guilt.

Guilt or innocence of one of the most highly publicized crimes of the '70s was not the formal issue yesterday, however. The issue to be resolved by the justices is whether there was excessive delay in bringing MacDonald to trial and whether, as a result, he should be permanently set free.

MacDonald's wife and two children were beaten and stabbed to death in the early morning hours of Feb. 17, 1970, at Fort Bragg, N.C., where MacDonald was stationed at the time. MacDonald was treated for 17 stab and puncture wounds.

The crime attracted national publicity when MacDonald claimed he and his family were the victims of members of a Charles Manson-style cult who invaded their home and brutalized the family.

First, the Army charged MacDonald with the murders. Then the Army dismissed the charges. Then, after a campaign by the murdered woman's father, the government reopened the case and recharged MacDonald in 1975. In 1979, a jury convicted the former Green Beret captain, who served one year of three consecutive life terms in prison before the 4th U.S. Circuit Court of Appeals reversed the conviction.

The appeals court ruled that the four-year lapse between the Army's first charges against MacDonald and the 1979 trial deprived him of his right to a speedy trial under the Sixth Amendment to the U.S. Constitution.

Crucial to the case is whether the elapsed time can be considered a "delay," even though MacDonald was free and not accused of any crime for about three of those years.

Government attorney Alan I. Horowitz told the justices yesterday that the constitutional speedy trial protection was designed to spare a defendant the protracted pain, expense, public condemnation and possible incarceration during a long period of uncertainty before being brought to trial.

MacDonald, he said, suffered none of those burdens. He wasn't even a defendant after the exoneration by the Army, Horowitz said, arguing that the time between dismissal of the charges and the later indictment should not count as "delay."

The government's obligation to provide a speedy trial was "deactivated" with the exoneration in 1971 and only reactivated with the indictment by a grand jury in 1975, he said.

Any other interpretation, he said, would require the government to rush investigations even when no one had been charged.

MacDonald's lawyer, Ralph S. Spritzer, disputed Horowitz' claim that MacDonald's suffering had terminated when the Army freed him in 1971. It continued from the day he was first accused until the present, Spritzer contended, even when no formal charges were pending.

In addition, he said, the delay severely damaged MacDonald's ability to defend himself when he finally went to trial.

Spritzer described how Helena Stoeckley, a potentially crucial witness in support of MacDonald's story, may have been unable to provide exculpatory testimony at the trial because of the delay. At MacDonald's trial, Stoeckley said she couldn't remember anything about the evening. (Since then, however, she has told reporters and private investigators that she was part of the "cult" that invaded MacDonald's house and that MacDonald did not commit the crimes. The FBI has recently interviewed her, according to government lawyers.)

"The concern," said Spritzer, "is that the Stoeckley story never got to the jury . . . . She took the stand and said she had no recollection."

"Isn't it possible that she would have said the same thing the day after the event? " said Justice William H. Rehnquist, who also asked if it was possible Stoeckley was not present the night of the murders.

"Yes," said Spritzer. "But we don't know that."

After the arguments, MacDonald, 38, who now lives in California, was asked what he was thinking during the hearing. "I was thinking I shouldn't even be here in the first place. I'm innocent and I've always been innocent."

Asked what he was thinking, Alfred Kassab, who has devoted much of the past decade to attempts to prove MacDonald killed his daughter, Colette, told reporters, "I was thinking that no one should be able to commit three murders and get off on a technicality."