THE WAR DECISION is bearing down on President Bush. If Saddam Hussein refuses to relinquish Kuwait a few weeks from now, Bush may have to decide whether the time has come to pull the trigger, putting thousands of lives and perhaps his presidency at risk for the purpose of resisting aggression in the Persian Gulf.

No one can know the precise situation Bush will face in the next month or two when he must make this momentous decision. But clues to his possible reactions can be found in the two very distinct faces that Bush has shown the nation and the world since Saddam's troops invaded Kuwait.

One of those faces belongs to a figure who might be described as the Statesman, a spiritual descendant of the American foreign policy establishment and the "wise men" who dominated it in the years from World War II to Vietnam. In this role, as an internationalist, a staunch foe of aggression, an exponent of American moral leadership abroad who seeks to shape a "new world order," Bush has used the crisis to demonstrate that, despite his youthful urge to flee the drawing rooms of the East Coast, he remains committed to the highest ideals of the establishment.

The Statesman, an aristocrat willing to sacrifice his popularity for the "right" decision in history, may well, in the current circumstances, go to war.

Bush's other face belongs to the Politician. Letting his emotions run away with his rhetoric, displaying a campaigner's zeal, Bush has sometimes allowed the confrontation with Saddam to be debased into a name-calling contest. Stung by criticism that he lacks conviction on this and other issues, the Politician protests too much that he is unyielding on matters of principle. But despite these protestations, the Politician may in fact be more cautious when it comes to war. He may decide that a costly and difficult fight is just not worth the risk.

At some point, the decision to go to war tests Bush in both these roles. If the Statesman decides that the only way to expel Saddam from Kuwait is with force, he cannot ignore the calculations of the Politician about how it will be received at home. Nor can the Statesman long survive without effective domestic political skills. Already, this has proven to be Bush's weakest point in the gulf crisis.

The president has succeeded beyond expectations at marshalling international support for the alliance against Iraq. But he has often seemed inarticulate and contradictory in attempting to explain his goals to the American public. And, at a critical moment, when he decided to nearly double the size of the military force in Operation Desert Shield, Bush seems to have given almost no thought to the reaction in Congress. The result was a political backlash that undercut the original purpose of expanding the military threat.

In trying to assess which of these conflicting impulses will dominate Bush's final decision, let's look first at how he has performed in his Statesman role so far.

Bush recently summoned to the White House a group of ambassadors from countries that have joined the alliance against Iraq. According to a well-informed source, Bush said that if he had to make the decision to go to war, he hoped he would have the support of the Congress and the American people. If he didn't have the support of Congress, Bush said, he hoped he would have the support of the American people.

If he didn't have that either, he said, he would not be deterred from going to war if it was the right thing to do.

This may be bluster, but it is also the underlying attitude that has led many people who know Bush, both inside the administration and outside it, to conclude that he is prepared to take the nation to war. Whatever others may say about his management of this crisis, Bush fashions himself as making the "right" decisions for history.

"No question, you do not placate an aggressor," he told Time magazine in an interview published last week. "You do not reward aggression. There's a lot of historical precedent to look at on this one."

In another instance, Bush was chatting with a group of friends at a luncheon recently when one guest suggested, indirectly, that a war would not be very popular at home. The guest drew a stern rebuke from the president who insisted that he was not being guided by crass political calculations. What he may be guided by is a thread that runs deep through his own life and times. Like the "wise men" chronicled by authors Walter Isaacson and Evan Thomas in their 1986 study of six influential men who shaped American policy after World War II, Bush can trace his own roots back to bastions of the establishment such as Andover and Yale. His father, Prescott Bush, was a friend and business associate of these men, including Robert Lovett and W. Averell Harriman. They were an elite group of public servants who helped create a new world order from the ashes of the war. They steered the United States away from isolationism and toward a new and difficult international role, one that eventually foundered in Vietnam.

Although Bush as a young man rebelled from the world of his parents, he did not abandon the world view of the establishment.

In his new biography of Col. Henry Stimson, author Godfrey Hodgson recalls Stimson's addresses at Andover and Yale in 1940, as war clouds loomed in Europe. Defying the isolationists in his Republican Party, Stimson made the case for conscription, national preparedness and, if need be, war. The speech was followed a few days later by Roosevelt's offer to Stimson to be secretary of war. Two years later, Stimson, again at Andover for commencement, warned the class of 1942 that the war would be a long ordeal, and that while the nation needed fighting men, the young Andover graduates should continue on with their education.

Even before the speech, Bush had decided to enlist in the Navy on his 18th birthday. When his father asked him if hearing Stimson had changed the young Bush's mind about enlisting, he said it had not.

"You've got to remember that in the end of the '30s there was kind of an isolationist fervor in some quarters," Bush recalled in the Time interview. "People saying, 'Hey, that's not any of our business.' There's a parallel there for what some feel about the Persian Gulf today: Let somebody else figure this out. And it's my view that nobody can, except the United States."

In combat, Bush survived a brush with death when his plane was shot down in the Pacific. He experienced the horrors of war and has anguished ever since over the death of a family friend in his plane that day.

In the years after the war, when Bush struck out on his own in Texas, the "wise men" were steering the United States away from isolationism. Later, as Bush entered Texas politics in the mid-1960s, he embraced the world view of the establishment as then being applied to the conflict in Vietnam. "I am for our position in Vietnam, and opposed to those who want to pull out and hand Southeast Asia to the communist aggressors," Bush said in a 1965 debate over President Johnson's escalation of the war.

According to Hodgson, "To oppose isolationism . . . . was the bedrock of American foreign policy for 20 postwar years. The war had taught that appeasement was a disaster, because there were wicked men in the world who could be restrained only by force. The lesson was that force might indeed be justified and military power essential."

This lesson is echoed repeatedly in the justifications offered today by Bush and Secretary of State James A. Baker III for the largest American military deployment since the Vietnam war.

"We must send a signal to any would-be Saddam Hussein that the world will not tolerate tyrants who violate every standard of civilized behavior -- invading, bullying and swallowing whole a peaceful neighbor," Bush told the troops in Saudi Arabia on his recent visit. "We can't hope to achieve our vision of a new world order . . . if the economic destiny of the world can be threatened by a vicious dictator."

"Recent events have surely proven that there is no substitute for American leadership," Bush said in his address to a joint session of Congress in September. "In the face of tyranny, let no one doubt American credibility and reliability. Let no one doubt our staying power." Now let's look at Bush in his role as Politician. It is hard to square the high principle of Bush the Statesman with the personal outbursts that have emanated from his political side. Bush seems to have adopted the same tactics against Saddam Hussein as he once employed against Geraldine Ferraro and Michael Dukakis. He has branded Saddam a dictator "worse than Hitler," promising to "kick a little ass." And declaring impetuously, "I've had it."

In these moments, Bush sounds more like the candidate of old who was taunted about the "wimp factor" than he does the leader of an international alliance trying to define the agenda of a new world order. His words are intended to scare, but they ring with a certain insecurity.

Having drawn a line in the sand for Saddam, Bush may now be hard pressed to redraw it. He may have had his fill of criticism that he has no basic principles, that even his "Read My Lips" pledge against tax increases was insincere. Bush remains extremely sensitive to what others think of him, particularly the doubts that polls have registered about his credibility.

He may want to prove something.

But political considerations push the president in the opposite direction at the same time. The Politician can bluff for a long time that he, like the Statesmen, is ready to go to war, but in the end, he may make a different kind of calculation.

The Politician in Bush is flexible and realistic. Bush demonstrated this right after the United Nations vote authorizing the use of force. Faced with a revolt in Congress over the new deployments he had ordered to the gulf, Bush suddenly announced he would send Baker to Baghdad to talk with Saddam. It was a political calculation, a pragmatic response to pressure.

Bush said he would not let American diplomats in Kuwait be chased out, either, but then just as abruptly evacuated them when Saddam's decision to release foreign hostages made the airlift a real possibility.

Despite the seeming public appetite for war now, Bush must sense that armed conflict on the Arabian penninsula is a huge roll of the dice for his entire presidency. Bush knows firsthand how Vietnam traumatized the nation and doomed Lyndon Johnson. It is easy for Bush to say that this would not be another Vietnam. "I pledge to you there will not be any murky ending," he said recently. But he cannot just "pledge" away the prospect of enormous loss of life and a groundswell of doubt for his cause.

The Statesman insists there should be no "partial" solutions to an act of "naked aggression." But the Politician, always more flexible, will be more amenable to compromise that achieves much of the original goal of expelling Iraq from Kuwait, particularly when it is weighed against the costs of war.

For example, suppose Saddam does make a partial retreat, stalling for time. Suppose he decides to give back most of Kuwait but keeps some territory, such as the two gulf islands and the disputed oilfield. Does Bush then declare war anyway? Could he go to the American people with the case that thousands of casualties are justified to make sure that Saddam vacates every inch of Kuwait? Would he risk these casualties for an issue that, prior to Aug. 2, the United States considered to be an inter-Arab border dispute? Even the United Nations has acknowledged that there could be negotiations on territory after a pullout.

An even greater test for the Politician would come if Saddam seeks some intangible reward for his aggression, such as the convening of an international Middle East peace conference to follow his withdrawal from Kuwait. Again, the Statesman may take the position that there can be no "linkage" with the broader Middle East conflict, not even a wink and a nod. But it is not so simple for the Politician.

Both Bush and Baker think that getting the Palestinian problem resolved is a high priority once the Gulf crisis is over. Moreover, Bush knows the way the world works -- he knows that such winks and nods are exchanged in world capitals every day, often with good effect.

During the Iran-contra affair, Bush was given an explicit description about the exchanges of weapons and hostages. But he insisted for a long time that he was not aware of any arms-for-hostage trade. It was there, but he chose not to see it. Ultimately, whatever his decision, Bush will have to integrate his roles as Statesman and Politician better than he has so far. The Statesman's rigidity needs to be softened by a Politician's understanding that flexibility is not a bad thing when thousands of lives are at stake. The Statesman, too, could use a politician's sense of the right time and the right way to think about a settlement that could preserve his place in history without the costs of war.

By the same token, if the Statesman in Bush concludes that war is absolutely necessary to achieve his goals, then he will have to be a better politician than he has been so far. He will need to show Americans he has the true convictions of a statesman. He will have to put flesh on the idea of a "new world order." He will have to blend the ideals of the Statesman and the zeal of the Politician to carry the nation along with his cause.

David Hoffman covers diplomatic affairs for The Washington Post.