With attacks on Judge Robert Bork's conservative philosophy falling short, his foes are switching their Senate confirmation strategy to the new and wholly unexpected issue of ''candor.''

Considering Bork's towering reputation, an assault on his character seems surprising. But his enemies are digging into the murky record of events 14 years ago immediately following his Oct. 20, 1973, firing of Archibald Cox as Watergate special prosecutor in an effort to find -- or manufacture -- a candor issue.

Their aim, as National Public Radio correspondent Nina Totenberg said Aug. 26 on ''All Things Considered,'' is to prove that ''Bork's version of events . . . conflicts directly with the accounts of others'' as to exactly what happened after Cox's ouster. Managers of Bork's confirmation are well aware of what's coming. ''The candor question,'' one administration strategist told us. ''That's what it's coming to, that Judge Bork can't be trusted.''

The case comes down in minute detail to what he did or did not say and mean when he briefed the Cox Watergate investigating team the day after he replaced Elliot Richardson as acting attorney general and complied with President Nixon's order to fire Cox.

No precise record exists. But in his 1982 testimony to the Senate Judiciary Committee on his nomination to the Circuit Court of Appeals, Bork recalled that tense moment in these words: ''I told them that I wanted to continue as before with their investigation, that I would guarantee their independence, including their right to go to court to get the White House tapes or any other evidence they wanted. Therefore I ordered them to do precisely what they had been doing under Mr. Cox.''

Totenberg reported, based on an interview with him, that Cox's top aide, Henry Ruth, ''remembers the meeting quite differently.'' That raises the ''candor'' question. But when we talked to Ruth, he said: ''If Bork had had his druthers, of course he wanted to continue with the full investigation.'' However, added Ruth, neither Bork nor anyone else in the government knew exactly what Nixon would or would not do in the wake of Cox's ouster.

''I don't question his integrity,'' Ruth told us, ''but he just could not have been in a position to tell us all that {specified in his 1982 testimony} at that moment. I hope he will be more precise in his Supreme Court confirmation hearing.''

In fact, reaching back in his memory to that moment of constitutional crisis, Bork may have confused what he actually said that day with what he did say later -- after the ''firestorm'' broke and Nixon replaced Cox with Leon Jaworski and surrendered the Oval Office tapes.

A second Totenberg allegation of Bork's lack of candor involved his answer to a question from the American Bar Association committee that investigated his fitness for the Circuit Court of Appeals (and gave him the highest rating). Although ABA interviews with judicial prospects are supposed never to be made public, Totenberg obtained a copy of Bork's. In it, she reported, Bork said that after firing Cox he ''immediately began searching for another special prosecutor.''

Totenberg asks: Did Bork's search for a Cox replacement begin ''immediately,'' as he told the ABA panel, or not until Oct. 25, when Nixon, bending to the firestorm, announced that he would ask Bork to find a new prosecutor?

Such minute scrutiny of Bork's words in an effort to cast doubt on his integrity demonstrates the intensity of his opposition. But Richardson, the liberal Republican whose support for Bork has been steadfast and strong, told us: ''It certainly is unfair to hold any of this against Judge Bork. You've got to imagine the situation he was in. I feel certain there is nothing in any of this that would reflect on his integrity, from everything I know.''

The search for a collateral issue shows that the attack on Bork's philosophic convictions is falling short. That is not unusual in Supreme Court confirmation battles. Judicial or constitutional philosophy seldom denies confirmation. In Bork's case, southern Democrats who might be persuaded to vote ''no'' would run a grave political risk in view of the judge's positions on abortion, the death penalty and other social issues that have the juices flowing in Dixie.

But charges, no matter how farfetched, outrageous or ambiguous, that Bork is a man not to be trusted offer a safer platform from which to attack him. That could provide a nonideological lever to freeze the Supreme Court's present ideological makeup and foil Ronald Reagan.