William Cohen was a bold choice to lead the Department of Defense. He’s independent, candid and a man of conscience. Oh, and he’s a Republican.

Already sweating at dawn in their bulky fatigues, the recruits lumbered into formation to hear a few words from their leader. But the man before them in polo shirt and crisp khakis wasn’t about to offer the usual Army pep talk.

“America is a country of the most persistent idealism and the blandest cynicism,” quoth Secretary of Defense William S. Cohen, borrowing the words of a British commentator. “The race is on between our vitality and our decadence.”

The recruits listened with respectful silence, but as Cohen and his aides melted away toward their motorcade, one stubble-topped recruit blurted: “Poetry in the morning? Something different around here.”

William S. Cohen is decidedly something different. Indeed, the longtime lawmaker, novelist, poet, acolyte of conscience--and now overseer of the world’s most powerful military--is the boldest bit of casting in President Clinton’s second-term Cabinet.

A symbol of independence and soul-baring candor in his 24 years on Capitol Hill, the former Maine senator now fills a job where team play and reserve are held in highest value.

With scant managerial experience, though long familiar with defense issues, he is running a globe-girdling bureaucracy that has humbled some of the nation’s most skilled managers.

And he comes to the job as a Republican--and a man with some sharp-edged differences with the administration he now serves.

The secretary’s independent side seemed to make a brief appearance earlier this month on NBC’s “Meet the Press,” when he seemed to pointedly decline an opportunity to defend Clinton’s justifications for fund-raising from the White House premises.

This unlikely pairing of man and job came about because of Clinton’s hunch that the 56-year-old Cohen could be a “home run” Cabinet selection: a man with the skills and public appeal that could add sparkle to the administration, not to mention sweeten relations with the congressional GOP, and demonstrate again Clinton’s fundamental nonpartisanship.

But it will work only if Cohen finds his way around the hazards that have undone so many of his predecessors, including Les Aspin, another brainy lawmaker and the man Clinton picked at the outset of his first term.

There is, of course, no easy time to run the Pentagon. But with a tight budget, an unclear mission, a rising need for new gear, and troublesome internal social problems--sex, hazing and mysterious illness--this may not be the best moment for on-the-job training. Still, Cohen is trying to master it and master it quickly.

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On his first domestic tour as secretary, Cohen recently visited Fort Jackson and Lackland Air Force Base, in San Antonio, to meet recruits, look over installations and talk personnel issues. He chatted with Air Force brass about choosing specialties for recruits and the aptitude tests that are supposed to guide them.

“Those aptitude tests said back in high school that I should be a farmer,” Cohen said. “So here I am.”

The banter flows easily with the generals, whom he has known in his long years on the Senate Armed Services Committee. And with his good looks and tended appearance, he seems to be the model of the polished Washington politician.

But this public face can be a bit misleading. Cohen has another side: reserved and introspective. In his 1981 book about senatorial life, “Roll Call” (Simon & Schuster), Cohen lamented that he didn’t quite have the easy garrulity of many in his job. He feared he was “a loner, too serious and too rigid and academic in my approach to politics and people.”

Cohen has always been somewhat the outsider, by happenstance and by choice.

He grew up in a tough immigrant neighborhood of Bangor, Maine, the son of a baker of Russian-Jewish heritage (who wanted him to be an orthodontist) and a mother of Irish-Protestant descent. He learned to fight with his fists when he was small; some friends speculate that may account for his conviction that a strong defense is the best assurance of peace.

Cohen, who has one brother and one sister, excelled in sports and academics, and later drew attention in Washington as the photogenic young lawmaker who split from his party in votes to impeach President Nixon and to broaden the Iran-Contra investigation.

As a youth, Cohen decided that he wouldn’t have a bar mitzvah because his mother’s Protestant faith meant he would require a special conversion ceremony.

“I chose exclusion from the Jewish faith rather than accept the terms of confirmation,” he wrote later of his tearful, angry decision, acknowledging that “snapping the bonds of conformity carried with it a price tag.”

He went his own way on matters of less moment as well. Cohen proudly points out that as a basketball star at Bowdoin College in Maine, his weapon was a two-handed set shot--an “anachronism” even when he was playing, he says.

He stood out, too, for his powerful hankering to spill forth his thoughts on paper. He has written three self-revealing novels, three nonfiction works, two books of poetry. Another nonfiction book and a screenplay are in their final stages.

His writings range across the broadest field of subjects: defense strategy, the strengths and lamentable weaknesses of the American system, international espionage, man’s fate, and often, his own life and family.

Cohen has two grown sons, Kevin and Christopher, by his first wife, Diane, whom he divorced in 1987. Last year, on Valentine’s Day, he married Janet Langhart in a ceremony that brought out senators, military chiefs and Cohen’s longtime acquaintances Dan Rather and Sam Donaldson.

Langhart is a former model and former interviewer on Black Entertainment Television who runs her own public relations business. The couple lives in an apartment midway between Congress and the White House with a sweeping view of Pennsylvania Avenue.

Cohen leaves home these days at 6:30 a.m. to plunge into a work regimen much like those of his new military subordinates. He is punctual, systematic and perhaps a shade on the compulsive side.

He cataloged every book in his Senate office by the Library of Congress system. Old law partners in Maine say his case files from nearly 30 years ago were so neatly assembled and comprehensive that they are still used to represent clients.

His habits are apparent in the way he’s gone about learning his new job.

He has interviewed, or made plans to interview, almost every living predecessor about the job--among them Dick Cheney, Caspar Weinberger, Frank Carlucci and James Schlesinger. He had breakfast in January with Robert S. McNamara, whose undoing by the Vietnam War stands as the ultimate symbol of the dangers of this position.

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Cohen, of course, knew the rigors of this job from his long years on the armed services panel. Yet he jumped at the chance--after he and Clinton had a candid conversation about what they could do to ensure the arrangement would work out.

Clinton had long admired the Maine senator, a moderate on social issues and a conservative on defense matters, and had publicly mentioned him as a possible Cabinet secretary after his first presidential victory. Clinton began to like Cohen even more that year, when Cohen seemed to be the only Republican senator willing to visit the White House socially, while others shunned the company of the new commander in chief.

But Clinton saw two complications: Cohen’s lack of managerial experience--he had run nothing larger than a Senate office--and his past policy differences with the administration on such matters as Bosnia and Iraq.

Clinton and Cohen discussed secretaries of defense past: Cheney, with a congressional background, had done well as President Bush’s secretary of defense. But Aspin, also from the Hill, had flopped in a muddle of management miscues and tardy decisions.

To make sure that didn’t happen again, Cohen agreed to take on a team of lieutenants with strong experience managing the defense bureaucracy.

And the two agreed that when Cohen didn’t see eye to eye with the administration, that he would offer his views forcefully in private--then hold his peace in public.

The selection of Cohen didn’t please everybody. Former Senate Majority Leader George Mitchell, Cohen’s fellow Maine senator, confided to friends his annoyance that a Republican who had often voted against the administration’s line would be chosen for such a post, while he, the dutiful soldier, was passed over to be secretary of state in favor of Madeleine Albright.

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Defense secretaries, dealing with grave matters as they do, tend to keep their feelings discreetly concealed. But the statesmen, defense ministers and generals who will now sit across the negotiating table from Cohen can find out his feelings on most anything in his eight books.

The German officials with whom he met with earlier this month, for instance, could learn of Cohen’s fears that their nation’s current leadership might somehow share something with the Nazis who persecuted his father’s people.

In a poem, written during his congressional years, describing a casual official meeting with German officials, Cohen related what he found churning inside himself:

It’s all quite civilized

and proper

discussing trade and technology

over coffee and tea . . .

But do they see the flick of fear

in my eyes

at the click of an accent?

Chinese officials can discover from his book “Roll Call” that during a senatorial trip to Beijing, Cohen was amused to watch the late Chinese leader Deng Xiaoping at a Great Hall appearance hawking and spitting mightily into a spittoon--at a volume painfully amplified by a public address system. Deng, a chain smoker, “was completely unabashed,” Cohen wrote.

And the military briefers at the Pentagon can find out in the secretary’s oeuvre that he finds many of their routine sessions together as dull as they probably do.

In “The Double Man” (Morrow, 1985), a thriller he wrote with former Sen. Gary Hart, Cohen lamented the agonizing official briefings where low-level employees “standing ram-rod stiff before a slide projector recite elementary facts as dry as old bread crusts. Those who gave briefings generally hate them, too, regarding politicians as pompous dilettantes or pretentious fools.”

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Cohen says the biggest jolt in his move from Congress to the Pentagon’s E Ring, where the leadership resides, was simply the “tidal wave” of paperwork that spills across his desk daily. “No matter how much I whittle it down, it never stops coming.”

The flow comes partly because of a backlog of decisions the Pentagon now confronts. In the wholesale strategic review that’s now underway, officials are trying to calculate what kind of war they’re likely to fight in the years ahead, how much new hardware they need, how they can reorganize the bureaucracy, extract more savings and ensure the flow young talent.

This exercise and the budget--which has been cut by one-third (after inflation) since 1989--have been the main tasks of Cohen’s first days. And he has plunged into them in a manner designed to show that he’s boss. He has set tight deadlines, prodded the military chiefs to come up with areas for potential savings, and forbidden them to end-run him with direct appeals for spending to purse controllers in Congress.

Some outside experts say Cohen has made a skillful debut by portraying himself as generally in favor of all the big areas of spending: new hardware, high troop readiness and “quality of life” benefits for an active-duty force that since 1989 has shrunk by nearly 30% to 1.44 million.

At his confirmation hearing, “no one could put a glove on him,” says Lawrence Korb, a former defense official now at the Brookings Institution. “The question is about the future: Where do you spend the money? He’ll have to choose.”

Also hanging is the question of whether a man who has so often broken from the team to follow his conscience will find at some point that he cannot support the administration policy. Some say it might come over the deployment of troops in Bosnia (Cohen wants them out in mid-1998), or over future peacekeeping deployments (Cohen is cool to them).

But people who know Cohen say he and Clinton must have chewed over such differences carefully before he was hired. If there is a split, “I have to believe it could only be over some issue that he didn’t see on the horizon,” says Tim Woodcook, a Maine lawyer and old friend who has worked for Cohen in political and legislative roles.

These days, Cohen confesses with regret that his schedule is now too hectic for writing. Or at least, for much writing.

He still scribbles the stray thought on the back of an envelope or napkin. The flesh is weak, he confides, but “the spirit is willing.”