TRB RUNS AN affectionate hand across the ancient oak roll-top desk. "It's beginning to split--like me. I don't know how many millions of words have passed over it."

So TRB, also known as Richard L. Strout, the legendary liberal essayist of The New Republic, will file his last column later this month.

After 40 years of lashing the government like a latter-day Ezekiel every week in "TRB From Washington"--preaching common compassion, deriding factional rancor and ridiculing cant--"I hate to give it up," says Strout, who turned 85 Monday. But "I just wanted a little more freedom," a chance to "simplify my life" by concentrating full-time on The Christian Science Monitor, where he has been a reporter for the past 62 years.

Hendrik Hertzberg, editor of The New Republic, says, "He's been talking about giving it up for years, but he had a hell of a time convincing me that he was serious--the idea was unthinkable." However, "we won't retire the jersey," Hertzberg says. Although "we don't have anybody to do the column yet," it will continue under various anonymous writers until a new regular is found.

After all, TRB predates even Strout. Once called Washington Wire, it got its famous initials in the early years of this century, when TNR was published in New York. Then-editor Bruce Bliven had received a new political column from Baltimore Sun reporter Frank Kent, a friend of H.L. Mencken's. The piece was to be anonymous, and Bliven was uncertain how to sign it. On the way to the printer, Strout says, Bliven saw a sign for the Brooklyn Rapid Transit, reversed the initials, and had his moniker. As the authorship passed to such notables as Kenneth Crawford (later of Newsweek) and thence to Strout, the initials became the title of the column--and of Strout's collected essays, published in 1979 by Macmillan.

For decades "all the politicians have read him," says former FDR aide James Rowe. "He's always been regarded as the sophisticated moralist of this town. He was always giving us lectures--and we always needed them!"

Strout manages a diffident mumble in the face of this fame. "I simply gave my left-of-center, liberal interpretation of, um, let's see--11 presidents." (In his document-mounded office on 16th Street, newspaper photos of all of them are taped to the wall over his desk, across from the picture of the cruiser on which he covered the D-Day invasion.) But there is a proud glint in the eyes of the aged face with its balding eyebrows and left ear half eaten away by skin cancer ("I bought a sunlamp once, and I used to sleep under it").

A flicker, still, of his life-long iconoclasm. When the Nixon stone wall crumbled, pundits rejoiced that "the system worked." To Strout, it proved just the opposite: the fundamental weakness of a political structure which guarantees antipathy between the president and the Congress. "It's an obsession with me."

"We have a dangerously anachronistic form of government," says Strout. "We're the only country that has this purposely built-in antagonism between the Senate and the House, the Congress and the president. It leads to stalemate and deadlock," and to a quadrennial purge mentality by which "we destroy the president and then put another in his place who is supposed to have all the virtues his predecessor lacked. We did it with Carter, and we're doing it again now with Reagan." Instead, "I think a parliamentary system is better," but "we're trapped by the Founding Fathers."

Contempt for partisan squabbling is a perennial theme in Strout's essays, which won him the Pulitzer Prize special citation for commentary in 1978. His first TRB column, dated March 8, 1943, begins in an eerily contemporary key: "I wonder how well the country understands the pessimism that broods over Washington these days," what with Congress "in a state of blind revolt . . . striking out fiercely at the president, labor and 'bureaucrats,' " yet "not offering a constructive policy of its own." His latest, from the current, March 28, issue, complains that because the Constitution gives us "the only government in the world that separates executive and legislative powers . . . it's hard to know who's in charge." Moreover, "things are getting worse rather than better. Mixed with apathy there is often now a feeling of hopelessness: everybody can see the huge budget deficit overhang, but who is going to meet the crisis?" He concludes that in terms of legal impediments to forceful policy, "The score now is Founding Fathers, 1787; Visitors, 0."

So much for the preachments of 40 years. Well, says Strout, "I'm a journalist. We write on water. What you write is soon forgotten."

That's not what the young native of upstate New York was thinking after graduating from Harvard in 1919 ("Look," he says, pointing to the crimson cravat firmly clipped to his shirt, "this is my 50th reunion tie"), taking up journalism because "it was a restless generation after World War I, and because my friends had got over to Europe in the Army and I hadn't." By the time he was in uniform, the war had ended, but Strout went to England anyway, taking a job on a paper there before returning to find that "one of the most extraordinary things in my life had occurred. Idealism was in disgrace, Wilson was retired, isolationism was back . . . and a gang of conservative, conventional cronies under Henry Cabot Lodge was running America while Harding played poker." He worked briefly at The Boston Post ("My first assignment was to get photos of toddlers who'd been killed in auto accidents--I said, 'This isn't the job for me' ") before joining The Monitor in 1921.

That year, he covered his first presidential press conference. And for all his indignation at the state of government, he thought the other reporters' cool demeanor "seemed almost sacrilegious. I resented their questions." Even though at the end of the briefing, Harding, natty in plus-fours, "asked pleadingly, 'Go easy on me, gentlemen, because I am on my way to play golf.' "

Strout, too, was on his way. Three years later he joined The Monitor's Washington bureau and grew in conviction and exposure, meeting and measuring the principal figures of early- and mid-century politics. There was William Taft--"an enormous, 325-pound man" who "trimmed down after he once got stuck in a White House bath tub"--and Calvin Coolidge, "a media-manufactured folk myth" with a less than compelling intellect who once told reporters that "when many people are out of work, unemployment results." There was Harry Truman, who could be "imaginatively and wonderfully corny" on the stump, and caused a "personal humiliation" for many reporters, including Strout, who had written his election column describing the kind of president Thomas Dewey would make; FDR ("large, smiling, self-confident, magnetic") and RFK--"one of the few politicians who could quote Shakespeare and get away with it."

In the early '50s, he covered Sen. Joseph McCarthy: "He was a scoundrel and a skunk, with no regard for truth. He once said he had seen me standing up and shaking hands with a reporter from the Daily Worker. That could have ruined me!" Strout's accounts of McCarthy in The Monitor were singled out as "the best coverage of all" in Edwin Bayley's 1981 study, "Joe McCarthy and the Press." Strout's work was "highly descriptive, interpretive and lively," Bayley writes, and readers "knew not only what was being said but why it was said and what the consequences might be."

And in 1959 he followed Kruschev's cross-country tour along with hundreds of reporters and photographers. In San Francisco, "they wanted to show him what a supermarket looked like," and the press mob, desperate for access, went berserk. "We wrecked the place," says Strout, who ended up on top of a check-out counter ("I always try to climb something") in the melee. "At my feet was a woman who was passed out prostrate. We just stepped over her" ("Only fainted?" an over-stepper asked Strout later, "I thought she was dead!"), while a fist fight broke out between a photographer and butcher. "We asked later, 'Why were you fighting?' 'I just don't know,' he replied in an injured tone. 'He attacked me. I didn't do anything to him. I just stood on his meat.' "

Over the years, Strout became so esteemed for fairness that when Richard Nixon was elected, John Ehrlichman approached Strout to ask him what the first goals of the Nixon administration should be. Simple, said Strout: Emulate the example of Sweden for its democracy and social equity. The discussion ended rather abruptly thereafter, and Ehrlichman did not return for further counsel.

But what could Ehrlichman have expected from the man who believes that reporters should have "at their hearts a touch of anger," and yet "make affirmation of our belief guardedly." Strout has watched journalism evolve from the era of Hearst and the other "press lords" through the great print age of "interpretive pieces" to the staccato dispatches of radio and TV and "this USA Today, which is just a lot of little television shorts strung together. We get the news faster now, but we have to pay for it" in lack of depth and context.

Which reminds him: Strout, at 85, has another deadline to meet. He swivels his chair toward the old manual, the ratchet chatters as he loads the paper, and soon the age-spotted fingers fill the office with a constant rapid clack.

"He's a tiger," says Monitor bureau chief Godfrey Sperling. "Just by walking through that door he sets a standard of excellence for everyone in the office." Especially, says Sperling, the new reporters. "It shows them that they really have some distance to go when they look over there and see the old man at his desk."