Ten years ago today, US troops were readying for what would become known as the 100-hour war - a ground offensive that would end the Gulf war against Iraq and, political and military leaders expected, profoundly change America's place in the world.

When the shooting stopped on Feb. 27, the experts said the lessons of the war were crystal clear:

So overwhelming was American firepower that it would have to be used less and less; the mere threat would be enough to solve many problems.

So accurate were American bombs and defensive weapons that the danger of US casualties in future conflicts would dwindle almost to nothing.

So devastated was Iraq that the brutal dictator Saddam Hussein could not possibly survive.

So popular was the war that President George H.W. Bush was a shoo-in for reelection.

That's not quite the way any of it turned out.

Instead, the intervening decade saw Bush lose, Hussein survive, and the myth of American omnipotence debunked. American military operations overseas burgeoned - on the ground in Somalia, Haiti, and Bosnia, from the air in Sudan and Afghanistan, and both in Kosovo.

''We greatly overestimated the significance of the victory,'' said Andrew Bacevich, director of the Department of International Relations at Boston University, where a three-day retrospective on the Gulf War began yesterday. ''It was fatuous to assume that it laid the groundwork for a new international order.

''Famine in Somalia is completely different from the breakup of Yugoslavia, from genocide in Rwanda, and the terror campaign of Osama bin Laden,'' he said. ''The world turned out to be much more disorderly.''

Brent Scowcroft, who was Bush's national security adviser during the conflict, said yesterday that there was little the United States could have done differently in 1991. He said the spirit in which the Bush team drew up its strategy - relying on United Nations authorizations and Arab allies - ''is still valid ... and likely will continue among veterans of the Gulf war in the new administration.''

Those veterans, serving Bush's son, include Vice President Dick Cheney, Secretary of State Colin Powell, and a host of lesser officials.

Terry Scott, director of the national security program at Harvard University's Kennedy School of Government, said that while the grandest expectations of what the conflict had accomplished were not realized, the war did succeed in keeping Saddam Hussein bottled up.

''It precluded Iraq from dominating the Persian Gulf, the oil production, and the populations,'' Scott said. ''The Iraqis are still in a pretty tight box and have not been able to generate a lot of trouble up to now. So the gain is 10 years of relative stability in the Gulf.''

Efraim Inbar, a professor of strategic studies at Israel's Bar-Ilan University, targeted the administration of President Clinton, which he said was inept in its conduct of foreign affairs.

''Much of the impact of this war ... evaporated because of the weakness of American diplomacy,'' Inbar said. James Baker, former secretary of state, and Bush ''were perceived as strong men in the region. Clinton was not a strong man.''

''That is why some Arabs now cooperate less with the United States,'' he said. ''They are not so sure the United States will come to their help. The United States has cut its forces, and its political will to act is questioned.''

Nevertheless, there is broad con sensus that the significance of the Gulf war was overstated from the beginning. One reason, Scott said, is the persistent and wrongheaded idea among late 20th-century American leaders that air war is the answer to the public aversion to body bags.

''It's a very appealing concept - we fly, we bomb, they do what we want them to do,'' said Scott, who was an American general during the war. ''Aerial bombardment has not been and never will be the quick simple solution to combat. It is unlikely you will ever be able to bomb people into surrender.''

But since World War II, when the Strategic Bombing Survey showed most bombardments in Europe and Asia were not highly effective, the United States has tried repeatedly to make bombing work.

During the Korean War, ''we tried it on the North Koreans and the Chinese, and it didn't work there,'' Scott said. ''So we tried it in Vietnam, and it didn't work there.''

''We have to relearn about every 10 years that you cannot conduct a war from the air and achieve your objectives,'' he said. ''I don't think that will ever change.''

One element of the Gulf war's expected legacy that did not take hold in 1991 may be getting dusted off now. The Powell doctrine, enunciated by the new secretary of state when he was chairman of the Joint Chiefs of Staff, was supposed to ensure that US forces would be used abroad only when the mission was clear, public support was strong, and overwhelming force could deliver decisive victory.

Instead, Bacevich of BU said, troops were used under Clinton in situations ''where we did not have clear missions,'' and sometimes in the midst of an operation ''the mission would change. We sent troops to Bosnia in 1995 for one year. Six years later, they are still there, and will be for some time.''

That sort of thing, Scowcroft suggested, may change.

However, Inbar said, a primary legacy of the war is that it illustrated ''there are limits to American power when it comes to making changes to its liking in the Middle East.''

''Saddam is out of the box,'' he said, and UN sanctions designed to prevent rebuilding Iraq's forces have failed.