Robert H. Bork's most controversial action, which the Senate is certain to examine closely, was his firing of Watergate special prosecutor Archibald Cox in what became known as the "Saturday Night Massacre."

In hearings before the Senate Judiciary Committee on his confirmation as a judge in 1982, Bork defended the propriety of his actions on the night of Oct. 20, 1973, when he fired Cox after Attorney General Elliot L. Richardson and Deputy Attorney General William D. Ruckelshaus resigned rather than do so.

"There was never any possibility that the discharge of the special prosecutor would . . . hamper the investigation or the prosecutions of the special prosecutor's office," Bork testified.

"Neither the president nor anyone else at the White House ever suggested to me that I do anything to stop or hinder in any way those investigations. If I had been asked to do that, I would not have done it," he said.

Bork also said he acted "to contain a very dangerous situation, one that threatened the viability of the Department of Justice and of other parts of the executive branch."

After Richardson and Ruckelshaus resigned, Bork said, "There was nobody after me in the line of succession . . . . The only thing that weighed against doing what I did was personal fear of the consequences, and I could not let that, I think, control my decision."

Cox declined to comment yesterday.

Bork was not accused of interfering with the investigation, and Richardson and others involved have come to his defense. But Bork's involvement in the firing has given those who oppose Bork on ideological grounds additional ammunition to attack his nomination.

"It would be the ultimate chutzpah to appoint the same guy who fired Archie Cox at the same time the Justice Department is attacking the special prosecutor statute and the country is embroiled in Irangate," said Art Kropp, executive director of People for the American Way, a liberal group specializing in First Amendment issues.

Consumer activist Ralph Nader, who filed suit in federal court here asserting that Bork acted illegally in firing Cox, said, "Bork was the good soldier. He didn't have to participate. Obviously, he felt that continuity was more important than conscience."

Ruling in Nader's lawsuit in 1973, U.S. District Court Judge Gerhard A. Gesell wrote: "The firing of Archibald Cox in the absence of a finding of extraordinary impropriety was in clear violation of an existing Justice Department regulation having the force of law and was therefore illegal."

The U.S. Court of Appeals for the District of Columbia Circuit, to which Bork was later appointed, vacated that decision as moot.

Robert P. Davidow, a law professor at George Mason University, testified at Bork's confirmation hearing that Bork "was not merely violating a department regulation but also assisting the president in refusing to acknowledge the authority of the U.S. Court of Appeals, so it is a little more than just a technicality."

That court had upheld U.S. District Court Judge Judge John J. Sirica's order requiring President Richard M. Nixon to turn over tapes to Cox.

Appointing Bork to the appeals court "under these circumstances, and given the importance of the government's obedience to its own rules, is appalling," Davidow testified.

"The appointment . . . would be very poor symbolism indeed," Davidow said. "But . . . Bork's actions as a government official raise serious questions about the extent to which he, as a judge, would require the federal government to adhere to constitutional and other legal limitations."

Others defend Bork's actions, saying the question of whether his Watergate role should disqualify him from the bench was asked and answered during the 1982 hearing. Only one senator asked about the "massacre" and did not press Bork about it during the brief hearing.

"If it is troublesome {now}, then why wasn't it troublesome for the court of appeals?" asked Daniel J. Popeo of the conservative Washington Legal Foundation. "The fact that he's gone through one confirmation already works strongly in his favor."

In interviews with The Washington Post, Bork recalled being summoned to Richardson's office that famous Saturday. Ruckelshaus was also there, he said.

"I had no idea what my involvement was going to be," Bork said.

Richardson "was under pressure from the White House to fire Cox and . . . finally he said, 'I can't fire Cox.' And he couldn't . . . . Not with the promises he'd made."

According to Bork, Richardson turned to Ruckelshaus and asked, "Can you fire him, Bill?"

"Bill thought a minute and said no," Bork said, adding that Richardson then said to Bork, "Can you fire him, Bob?"

"I said, wait a minute, let me think," Bork said. "Finally, I said, 'Yeah, I can, but I'll resign. I'll fire him and resign.'

"And he said, 'Why would you do that? Why would you resign?' And I said I don't want to look like an apparatchik. He said, 'No, you've got to stay. The department needs continuity.' . . . . Finally, he came back and said, 'You've got to do it, carry it off.' "

Bork said in the interviews that he has never doubted that he was correct in firing Cox.

"I . . . was really not acclimated to Washington," he said. "I think I should have walked out of the White House that night, held a press conference instantly and said, 'Don't worry, the investigation is going on as before.' "