Many lessons of the gulf war are by now obvious: the decisiveness of air power, the irrelevance of the Arab "street," and the astonishing efficacy of high-tech weaponry. But one lesson has been largely overlooked. It has to do with American public opinion and the nature of presidential leadership.

Cast your mind back exactly seven months. On Aug. 1, you would have thought crazy anyone who suggested that President Bush would send more than 500,000 troops into the Arabian desert, that he would launch them in a massive ground offensive and that, at the point of maximum danger, 90 percent of the American people would support his conduct.Bush found a country still not fully recovered from Vietnam and embarked on a difficult and risky foreign adventure. At every stage, he brought the country with him. It was a remarkable feat of domestic diplomacy, all the more remarkable for being almost imperceptible.

That is because he didn't do it the usual way. The usual way to inspire is through language. Historically, leaders rally a nation to war, with ringing rhetoric. Think of FDR and Churchill.

Bush is no Franklin Roosevelt. Bush is a president so devoid of rhetorical skill - Wednesday night's flat victory speech is but the latest proof - that he rarely addresses the nation.

So how did he do it? He did it, as they say in the Middle East, by creating facts. Four times since Aug. 2, he made unilateral decisions that were bold and, to the extent that anyone had considered them at all, generally unpopular. Yet, each action reshaped the debate and came to be seen as necessary if not inevitable - and correct.

Fact 1, Aug. 7: the initial American troop deployment. Three days earlier, the Gallup poll asked Americans about sending troops to defend Kuwait. It found 56 percent opposed. The deployment announcement (framed, to be sure, as a defense of Saudi Arabia) drew immediate, 81 percent approval. By the time critics mounted opposition to Bush's further actions, the initial deployment had become a matter of national consensus.

Fact 2, Nov. 8: doubling the ground troops. That put the United States on a war footing and created a great wave of Democratic opposition. But there was little the Democrats could do.

Bush had used his power as commander in chief to create a political fact - the doubling amounted to a commitment of American prestige and a declaration of American resolve to see Iraq out of Kuwait - that was nearly impossible for the opposition to reverse. Had the Democrats forced a withdrawal or rotation of these new troops, the whole allied effort would have been undone. The Democrats were boxed in.

Which is why they concentrated their fire on the looming Fact 3, the launching of the war itself. But here, too, Bush had constrained the debate with more facts, in this case, the already established United Nations deadline.

For Democrats to oppose the war at that point, they had to be willing to vitiate the deadline, upset the coalition and undermine the very idea of collective security, an idea dear to Democratic hearts. Having prepared the battlefield, as the military briefers like to say, Bush won. By a hair, but he won.

Then Fact 4, the ground war. As with the air war, an initially apprehensive public rallied hugely behind the policy. Ten days before the ground war, the CBS-New York Times poll found only 11 percent of Americans in favor of launching one. When asked again the day after the ground war started, 75 percent approved.

The cynics will say that this proves only that nothing succeeds like success. Yes, but no one knows in advance where success lies. Particularly in war, one chooses very much in the dark. The point is that if you choose well, even if unpopularly, the people will follow.

It must be admitted that Bush was helped in all this by two factors not of his making: an inept enemy and a just cause. Yes, but remember how roundly, and correctly, Bush was criticized for being unable to articulate the justness of the cause.

As for Saddam's now demonstrated ineptness: Remember that just weeks ago the conventional wisdom cast him as supremely wily and resourceful. Not many were predicting an easy campaign.

As a shaper of public opinion, the bully pulpit is overrated. The powers of the presidency, if skillfully deployed, are enough to move the nation.

Bush managed to rally a reluctant nation to a successful war not with inspiring words or soaring visions, but with a series of shrewd and forcing actions.

Military schools will long study Gen. H. Norman Schwarzkopf's march through the gulf. Government schools will study Bush's march through Washington.