THE TRIAL balloon that had been drifting through Washington's political stratosphere for a couple of weeks suddenly was being propelled by more than hot air.

Zbigniew Brzezinski, the president's ubiquitious national security adviser, seemed to be taking himself out of the Secretary of State Sweepstakes.

"Who the hell wants that job?" he scoffed over lunch, announcing to reporters that his personal choice as Cyrus Vance's successor, when he bows out at the end of this term if Carter wins reelection, will be the No. 2 man in that foggy bottom of foreign affairs they call the State Department.

Which meant, of course, Warren Christopher, he of the color-me-gray persona, quizical brows and, for three years now, the Gaston to Cy Vance's Alfonse.

Which also meant, of course, in a city like Washington where hearing a disclaimer is not necessarily believing one, that the use by the White House of the State Department as a political as well as diplomatic strategy will continue neck-and-neck to the Novmeber finish line.

So while Warren Christopher, 54, the quinessential corporate lawyer variously known as times as "Mr. Neat," "Mr. Cool," "Mr. Human Rights," and Cy Vance's "alter ego" (I hope that's not too self-congradulatory," he worries), goes into the home stretch as the quinessential deputy secretary of state, supporters are rallying to help him shake that image.

"Where did you get you new campaign manager?" an administration official asked Christopher the day after Brzezinski's lunch. Christopher expressed mystification.

A Christopher critic remembers something that Lucius Clay once said about chiefs of staff: Always choose an utterly faceless man who will mind the store and have no ambition because it leaves you free to be the liberal, loveable, likeable guy you are with a well-protected flank.

"What worries me," says a State Department colleague, "is that Chris is the perfect No. 2 -- never out in front of Vance, never second-guessing him. When you look at the A list (of names like Robert Strauss, Lloyd Culter and Sol Linowitz) for the No. 1 job, No. 2 is apt to be forgotten because he did the job so well."

"Secetary Vance has asked me to prepare myself to serve as his alter ego in the broadest sense. That means that to the extent possible I will try to become fully informed on all of the matters that he is involved in and all of the matters that are before our department . . . I hope to be able to prepare myself to stand in for the secretary when, as so often happens, he is out of the country or is required to be in two places at the same time." -- Christopher at his Feb. 24, 1977, confirmation hearings before the Senate Foreign Relations Committee.

In the heat of the flip before it flopped under mounting pressure against the American vote against Israel at the United Nations, Jimmy Carter was trackyng down Cy Vance in Chicago. On the White House griddle for 1 1/2 hours, goes one story, was Mr. Cool arguing against panic.

The same Mr. Cool, you will remember, whom furious Brazilians once sent packing over human rights versus military assistance pacts and nuclear proliferation; who jumped in with the lifesaver as the Panama Canal treaties were about to go under in the wake of presidential support for U.S. intervention; who angry Taiwanese mobs pelted with eggs and ran through the bamboo gauntlet as the U.S. prepared to recognize Red China.

"We were sitting ducks," remembers former ambassador Leonard Unger riding with Christopher in the lead car as it left Taipei's airport. A few minutes earlier, Taiwan's vice foreign minister had offered an ominous-sounding welcome.

"We knew the reception would be cool," recalls one member of the American party, "but we didn't expect violence."

As Christopher's car moved out, angry crowds prodded it with bamboo sticks, breaking windows and even cutting Unger and Christopher on the face.

"We speculated on why this had been allowed to happen," says Unger, describing how ahead of them on the flatbed of a truck a camera crew recorded the scene.

Some in the group later argued for aborting the mission and returning to Washington but Christopher decided to go through with it.

By 4 a.m. when everybody had regrouped at the U.S. military compound, Christopher was ready with some levity.

"Egg shampoo," he observed with a flash of the Christopher wit, "is the 'in' thing this year."

Hazardous game, indeed, this diplomacy.

Why just this January Christopher flew off to Europe to drum up support for sanctions against the Soviet Union over its invasion of Afghanistan. As administration advance man it fell to him to seek a common ground among Allied intellects and personalities of widely differing opinions about his mission.

In the Federal Republic of Germany where officials of Helmut Schmidit's government asked whether the Carter administration was serious about boycotting the Olympic Games in Moscow, Christopher assured them it was not.

By the weekend, back in Washington, Jimmy Carter prepared to go on NBC Television to "Meet the Press". Two hous befor air time he cabled Schmidt a change of policy: He would call for a boycott after all.

"I think," says Warren Christopher, sitting erect and expressionless behind the gleaming walnut desk at the State Department and contemplating a question about consistency in U.S. foreign policy, "that events force on us the need to adjust. You can't prescribe a formula for what you're going to do over the next six months or next 12 months. You have to lay down a general set of principles and try to follow them. You have to adapt those principles to changing events."

He is parsimonious with his smiles. As a former associate says, "When he smiles it last for just a second and it's painful."

His shining hour, say some supporters, was when he withstood pressure to start up military equipment for Guatemala. Others say it was Panama.

"He was the point man for the whole United States government," says attorney William Rogers, a former assistant secretary of state for Latin America whom Christopher tapped for the delicate job of communications link between the two countries.

When Arizona Sen. Dennis DeConcini won acceptance by the president for his amendment calling for intervention should Panama ever be threatened, the treaties' chances for success took a nose dive.

They were the capstone for the whole Carter administration foreign policy up to that point, and jumping in to the rescue went Christopher. His success won him a powerful White House ally, Hamilton Jordan, though Christopher is careful to avoid even a hint of self congratulations.

Some people are quick to cite himan rights, which has been Christopher's baby since the beginning, as yet another example of adapting principles.

"If human rights were an Erector set" says an associate, "Chris tightened the screws and got it working."

Others looking on have been less enthusiastic, seeing U.S. efforts as a kind of carrot-and-stick approach of using financial aid to force military regimes to case up on human rights violations.

One of the few times anybody ever remembers hearing that Christopher could get angry ("He never gets angry except on purpose," says a friend), came when Rep. Charles Wilson (d-Tex.) clained Christopher chewed him out over a pro-Somoza press conference he staged in Managua. The State Department's Nicaragua policy, Wilson maintained, was being run by "a bunch of adolescent anarchists" and leaving the door wide open for communism to breed in the Caribbean.

It had been Christopher who okayed the agreement authorizing $12 million in foreign military sales credits to the Somoza government in 1977, a promise the U.S. later broke."Chris may view that now as the wrong decision because it gave Somoza the idea he could hang on forever," says a former State Department official.

Rep. Wilson thinks Christopher has changed a lot since those days when he was "a very naive inexperienced ideologue." If he is "a tough paragmatist," much of it is due to events in Afghanistan and Pakistan, says Wilson.

"No question that human rights in Pakistan are severe," says a State Department source. "But what we've discovered is that we can assist a country in protecting its geographical integrity and have an on-going working relationship though not necessarily embrace the individual at the head."

Says Christopher: "Our foreign policy hasn't changed. We still have the same set of precepts: Strengthen America, work with the allies, work with the Third World, try to settle regional conflicts, be concerned about human rights, pursue nuclear nonproliferation. But we have to adapt those things to such changing events as the crisis in Iran or the Soviet invasion of Afghanistan. I think the public has the preception that there are changes."

"Diplomacy is not a system of moral philosophy," wrote Harold Nicholson. "It is as Sir Ernest Satow defined it, 'the application of intelligence and tact to the conduct of official relations between the governments of independent states'. The worst kind of diplomatists are missionaries, fanatics and lawyers; the best kind are the reasonable and humane skeptics."

There are lots of skeptics in Washington; how humane or reasonable is another question. There are also lots of lawyers, of which Warren Christopher, again is the quintessential example.

"Sharp-elbowed," say a former State Department official of Christopher's professional agressiveness.

"Someone once wrote he had 'exquisite judgment,'" remembers San Francisco attorney Robert Raven, chairman of the American Bar Association's Standing Committee on the Federal Judiciary. "I told my wife if that were about anybody else I'd hoot. But it sums up Christopher perfectly."

"The kind of lawyer you'd like to be your wife's divorce lawyer," says Charlie Wilson, "always seeing the other side, always going the extra mile."

"A very quick study," says a close associate. "It doesn't take him long to piece out the essentials, of putting together alternatives, at synthesizing materials and viewpoints, of cutting through the chaff. His innovations come in the different ways to approace a porblem."

From Stanford University law school classmate Fred Dutton comes: "Washington is big on people trying to sell their won position. But chris will give you Option A, Option B, Option C and he doesn't load up one option over another because it's the one he prefers."

Says Christopher of his highly organized and methodical lawyer-like practices: "I have a lot more confidence in my own judgment after I've heard a disparate group of people." And then: "I don't think you can carry out our foreign policy as a matter of logic or as a matter of pure analysis. Ultimately you have to persuade the American people of the rightnes of the course you're following . . . "

With that characteristic self-effacing manner that drives some critics up the wall, Christopher says that while some people around him have made foreign policy their lives, "I come to it from a different background."

Which says longtime observers of deputy secretaries-of-anything in Washington, is not all that shocking or even unusual.

California's former governor Pat Brown probably discovered him. "A young genius on the way up," Brown remembers. He made him and several others from that "remarkable" Stanford University law school class of 1949 part of his "brain trust" when he ran against William Knowland for governor. Brown says Christopher wrote his inaugural speech and "gave me the slogan 'irresponsible liberalism'."

Later, Brown named Christopher, a highly successful member of the powerful Los Angeles law firm of O'Melveny & Myers, to the McCone commision studying the Watts riots. Another time he assigned him to study what constituted air pollution in California.

"It was an extraordinary bit of work because he wrote what amounted to the first definition of it.There simply wasn't any information before that," says Brown.

Others who remember Christopher say he was part of that very liberal California Democratic establishment that developed the "club" system based on issues rather than patronage. Pat Brown's support emanated from there, Alan Cranston and John Tunney came up from it, and through it's fallen on hard times recently, Jerry Brown drew from it.

Some of those liberal Democratic friendships had been forged earlier at Stanford -- with the Hufstedlers, Shirley (new Secretary of Education) and her husband, Los Angeles Attorney Seth; Washington attorney Fred Dutton; Hale Champion, former undersecretary of Health, Education and Welfare.

Christopher had been the first editor of the law review, and a workaholic then, too. "But unlike the rest of us after staying up all night to meet the review's quarterly deadlines, Chris looked like he'd just stepped out of the shower. We called him 'Mr. Neat,'" says Seth Hufstedler.

Reserved by nature then, too, it didn't preclude his competitive instincts. He was a runner and a tennis player (he still does both) and a champion at something called "wasketball" involving two wastebaskets at each end of the law review office.

He arrived at Stanford by way of the U.S. Navy, a debate team scholarship at the University of Redlands, Hollywood High School and, much earlier, Scranton, N.D. (pop. 300), where the Russion thistles rolled across te prairies and piled up against the fences.

Son of a banker and one of four children, Christopher says growing up in a small Midwest town gave him a different perspective. It was the Depression an do "I remember driving with my father around various farms -- he was trying to avoid having to foreclose on them.

When his father fell ill, the family moved to California. A newspaper boy first, he soon became a stringer for The Hollywood Citizen News, earning 10 cents an inch writing high-school sports.

("It's certainly hard to talk about oneself," he says uncomfortably in the middle of an interview in his office atthe State Department.)

"He's the same wiry guy today he was in school with the same perpetually worried look on his face," says Los Angeles attorney H. Melvin Swift, who shared a room and a car with him until Christopher got married and Swift got the car.

The former Joan Workman bore Christopher a daughter, Lynn, but eventually divorced him to marry anoterh law-school classmate, Richard Jencks, later to become a vice president of CBS.

In 1949 Christopher came to Washington the first time -- as law clerk to the late Supreme Court Justice William O. Douglas, the first ever to be chosen from Stanford.

His second move to Washington came in 1967 when Ramsey Clark named him deputy attorney general. By then he was married to Marie Wyllis, a pretty blond former school teacher whom he had met on a blind date in Los Angeles in 1956 and had asked to marry him two weeks later. They have three children: Scott, 22, Thomas, 20, and Kristen, 16.

Now, Christopher's third Washington residency, the family home is a two-story brick colonial is Spring Valley. He leaves it every morning around 5:30 to run through the neighborhood before most people are awake.

A "typical" day progresses from breakfat-table talk with his wife (minus newspapers -- though being what friends call a "news junkie" he does a quick initial read en route to the office). By 7:30 a.m. he's with Vance, who divides up the day's tasks whether it's briefing a 'hill committee, developing a particular policy from ideas sketched by Vance or attending a meeting at the White House.

About as close to undisguised excitement as the normally reserved Christopher gets is when he's talking about his work on the Hill and three "absorbing" pieces of legislation in which he had a hand: the Taiwan Relations Act, paving the way for normalization of relations with Mainland China; lifting the embargo on Turkey; and providing high-performance aircraft to Saudi Arabia.

Throughout his day Christopher "chews right through the in-box because being on top of the paper flow is how you maintain influence," says a source.

Christopher says he tries to stay "current all across the board" so that he can be instantly responsive to the president when Vance is out of town. He's found it "a relative good formula because I'm apt to have to move in on short notice even when the secretary is here."

He's home between 7:30 and 8 p.m. where the nightly ritual is swapping the day's experiences over dirnks with his wife. She draws from her part-time job in a tennis shop and sometimes he discusses his probles in great detail and "wants to talk about his options," she says, "and is a lot more tense" since the Iranian crisis developed.

Sometimes they catch a Sunday movie, usually they play tennis on weekends with longtime friends CBS correspondent Bob Pierpoint and his wife or Frank Loy, deputy coordinator for refugee affairs, and occasionally they go out to dinner.

"This is a hard city on spouses," Christopher says. "In the relatively little time we have, we often try to spend it together privately. I hope it's not antisocial."

What may have affected his attitude as much as anything towards Washington social life, he says, is that as a lawyer, he has this "old-fashioned concept that a lawyer ought to avoid publicity."

Others viewing Christopher call him "a corporate lawyer who likes to have his life and the world tied up in a precise little package -- except that the Middle East has not been a nice tidy little package."

He is seen as extremely influential with Vance. They got to know each other well back in 1967 when Vance was deputy secretary of Defence and Christopher was deputy attorney general and they were the principle civilians looking into the Detroit roits.

Through Vance, says associates, Christopher has had considerable influence with Jimmy Carter. Characteristically, he leaves the public posturing to higher profiled personalities.

"I don't think personalities have inhibited us in carrying out the president's foreign policy," he says, choosing words as carefully as he might for a bilateral agreement. "It would be a dull and ineffective administration that didn't have some differences of view. If the president got only one set of views, he would be ill-served by his advisers."

In Warren Christopher, at least, Capitol Hill found the consummate administration witness. Unlike Brzezinski, who claims that dealing with Congress in an aspect of statecrate that puts him off, Christopher enjoys the courtroom like give-and-take.

"I find it helpful to hear what they're saying about how people feel. If you divorce foreign policy from the view of the American public," he counsels in that lawyerly fashion sometimes mistaken for lecturing, "you'd be making a very serious mistake. We need to listen to the voice of the people in the land who help guide us."

Rep. Tom Harkin (D-Ia.) says he'll never forget the day Christopher appeared before the House Foreign Affairs Committee right after the Iranians had taken the American hostages.

"I mean some of the members just went bananas, but for an hour and a half, in one of the best performances I've ever seen, Warren Christopher reassured us that the steps the U.S. was taking were well thought out towards getting those hostages out alive. I felt sorry for him , the poor man, but he really held his cool."

The Khyber Kaper started out as solo number by Christopher with scheduled stops in Pakistan and Saudi Arabia but no side show. Then Brzezinski signed on and so did a half-dozen reporters and before anybody knew it they had this road show of rifles, refugees and rousing rhetoric.

Officially, Brzezinski handled the global overview while Christopher did the down-on-the-ground detail work of negotiating responsibility on bilateral issues. Such as the 1959 agreement with Pakistan and how or whether it might be modified.

In long private sessions with President Zia, the word was that it was Christopher hammering home the fact that the U.S. would not upgrade the agreement into a treaty. Later, it was Brzenzinsky, not Christopher, who presided at press briefings ("Who do you think defined it all for Brzezinski?" observed one Christopherphile.)

Out in the open at a dinner Zia gave, the focus was on Brzezinski, Christopher wasn't even mentioned on the fancy gold-lettered invitation. That night he sat considerably below the salt.

There were rumors that Christopher had a little fence-mending to do, his visit to Pakistan the year before having ended on a sour note. Then he was supposed to have lectured Zia on the fallacies of Pakistan's nuclear program ("more a factual statement than a lecture," says someone who was there).

Which brings us back to ballons and how trial ones stay afloat. Unlikely couple diplomats, intimates of each suggest that Zbigniew Brzezinski and Warren Christopher get along just fine together. Indeed, funnier detentes have happened in Washington.

By all accounts it doesn't bother Christopher in the least being overshadowed by Brzezinski.

"Christopher has a better feel for the way foreign governments are preceived by the congress," says one source, "and Zbig takes the higher profile, with those governments focusing on him more."

Occasionally they might share the spotlight, as they did at the refugee camp a few weeks back when Brzezinski assured the Afghans that God and U.S. were on their side. Then turning to Christopher, he invited: "Chris, why don't you say something?"