WASHINGTON--It was after 7 p.m. and James D. St. Clair, President Nixon's defense lawyer, had not yet returned to his office. This had been another long and frustrating day for him--sitting behind closed doors with the House Judiciary Committee, watching the evidence against his client pile up.

In room 188 1/2 of the Old Executive Office Building, St. Clair's secretary was typing letters on White House stationery; in a back room, members of his staff watched their boss on television as he arrived on Capitol Hill that morning.

J. Fred Buzhardt, Counsel to the President, glided through the door in a cream-colored suit. "He's not back yet?" Buzhardt asked St. Clair's secretary. He paced the gold carpet of the outer office, puffing gingerly on a cigarette. "They oughta call us and let us know if they want a rescue team."

Buzhardt is an authority on rescue teams. He and Leonard Garment comprised Nixon's Watergate rescue team until they were rescued by University of Texas professor Charles Alan Wright, who was rescued by Boston trial lawyer James Draper St. Clair. But it is unlikely that St. Clair will need rescuing. Since he began working for Nixon last January 2, St. Clair has won the President much-needed time, using a strategy of delay, diversion and denial. Nixon might be impeached and convicted, but he will not be able to claim incompetence of counsel. In fact, some believe that it is St. Clair's cunning alone that enables Nixon to cling to office.

Buzhardt grew tired of waiting and left the office--it was once his office before mysterious gaps and "sinister forces" spoiled things--and walked down the hall to his new office, which once belonged to John Dean, the first White House lawyer who tried to rescue Nixon from Watergate.

Soon afterwards, St. Clair wearily shuffled in--short, dumpy, exhausted. When St. Clair smiles, he looks sly and devious--it is a homely smile (there is a large gap between his front teeth), a mocking smile, and he looks remarkably like the "Silver Fox" for which he is nicknamed. But St. Clair was not smiling as he entered. He deposited a briefcase in his private office, then dropped himself deep into a chair at a small conference table and gave a long, loud sigh. He looked more like a wounded bear.

Why did he take Nixon's case? For fame, perhaps, but not for money (St. Clair gave up a practice reportedly worth $300,000 a year to become Nixon's lawyer for an annual salary of $42,500.) Also, St. Clair says he believes in making his counsel available to whomever most needs it. On that principle, he helped Joseph N. Welch battle Sen. Joseph McCarthy in the televised Army-McCarthy hearings in 1954; he helped the Boston School Department fight enforced racial balance; he argued against film censorship. Rev. William Sloane Coffin, whom St. Clair defended against charges of conspiracy to violate draft laws, once complained: "The trouble with St. Clair is that he is all case and no cause."

"I considered that a compliment," St. Clair said in an interview last week. Is it a compliment when applied to his handling of Nixon's case, too? "Positively," he said. "These gentlemen don't need causists. They need someone to represent them with some objectivity." The following are excerpts from that interview:

Q. Your office, when you took the job, was a graveyard for lawyers. You were stepping into a mess that one lawyer after another hadn't been able to cope with. Were you at all worried about what it would to your reputation?

A: No, I wasn't. I don't know that the description is accurate, either. But I intended to, and hope to be able to perform adequately as a lawyer, and as such I don't anticipate there will be anything derogatory to my personal reputation.

Q: I didn't mean that there would be anything derogatory, but that the experience would be frustrating, and ultimately, maybe a failing exercise...

A: That's the risk anyone takes when you start out on any law suit: You could lose, you know. And this is not to say that I anticipate losing this case--I do not--but that's, you know, a risk that you take in representing any client.

Q: When Archibald Cox became special prosecutor, he was quoted as saying that he anticipated being in Washington for several years, until the whole thing was wrapped up. What are your expectations?

A: Well, I hope that this matter will be concluded within the next several weeks.

Q: You were quoted as saying that you don't see yourself as defending Nixon individually, but rather the presidency. What do you mean by that?