AMERICA HAS taken the war in the Persian Gulf directly to Saddam Hussein's doorstep rather than putting its effort into liberating Kuwait immediately. The undeclared initial American war aim is to break Saddam's military machine in Iraq before he can escape the trap U.S. planners have prepared for him over the past five months.

Such an escape by Saddam has been labeled the "nightmare scenario" by Pentagon planners, who have consciously sought to preempt it with their Desert Storm operation. U.S. planning emphasizes moving quickly and massively to achieve U.S. goals before the international and domestic support George Bush has marshalled can be pulled apart by Iraqi military or political countermoves in Kuwait, Israel or elsewhere.

America's aim of fighting as much of the war as possible inside Iraq with air power -- whatever may be happening with respect to Iraqi withdrawal from Kuwait -- became apparent in the opening moments of the conflict, which occurred as darkness fell on Wednesday in the Middle East.

Hours before bombs exploding over Baghdad formally announced the war to the world, U.S. Army Apache attack helicopters carrying Special Forces units swooped from the sky and destroyed two Iraqi early warning radar sites just inside Iraq's frontier with Saudi Arabia. This attack, details of which remain blanketed in military secrecy, helped open the corridor to Baghdad flown by the F-117 stealth and other fighter bombers that carried out the first raids.

Opening the war on Iraqi soil also demonstrated that the United States went to war with considerable malice aforethought. The raids carried out in the first 72 hours of the war were all coordinated in a strategic three-day campaign that proceeded methodically from north to south -- from Iraq toward Kuwait. The Pentagon was determined to strike the more than 4,000 targets on its priority list before pausing to evaluate the campaign's overall effectiveness, according to two well informed sources.

The Desert Storm operation is intended in fact to forestall any kind of pause in operations until the United States is confident that Iraq's military capabilities, and particularly its chemical, biological and nuclear production facilities and missile force, have been eliminated.

"Now that hostilities have started, the objective has to be to fight our war, to follow our plan, and not to let Saddam Hussein lure us into fighting his war," a senior Pentagon official said. "He will want to fight us like he fought Iran, in a long, drawn-out ground war. We have to prevent that."

Immediately taking the war to Saddam rather than emphasizing the liberation of Kuwait is the most effective way for the Bush administration to weave together the military, diplomatic and political strands of a war that is a completely new phenomenon on all those fronts. The world has changed in the past four days, passing in a baptism of fire from a time shaped by World War II and Vietnam into a future that will bear the mark of the Gulf war, however it turns out.

The most obvious change for the moment is in the technology of warfare. The news conveyed to congressional leaders on Thursday that 51 of the 52 Tomahawk cruise missiles launched in the first wave of attacks had hit their targets helped prompt Sen. Sam Nunn (D-Ga.) to abandon his usual understatement and declare that the world had entered "a new era of warfare." The apparent effectiveness of the electronic jamming of Iraqi communications and radar from the air at the battle's outset reinforced that impression.

But the changes the gulf crisis will bring are far broader. "This is the first major crisis that the United States has worked without having the Soviet Union working the other side," says Rep. Les Aspin (D-Wis.), the chairman of the House Armed Services Committee and principal author of a study on U.S. military options in the Gulf that foreshadowed with remarkable accuracy the shape and direction American actions would take.

"This is going to be the defining moment for America's role in the world for a decade or more to come," Aspin asserts. "How we come out of this will determine whether we can or cannot still call on force to achieve our goals abroad. How we come out of this will determine whether we can or cannot use the United Nations to achieve our goals. How we come out of this will determine our relations not only with the states of the Middle East, but also of Europe. It will establish who we can work with in the future, and how." By starting Desert Storm with massive surgical air strikes against targets all across Iraq, the United States appears to have preempted the problem of conflicting war aims within the international coalition America leads. Initial conversations in the coalition indicated that countries would react in different ways to a situation in which Iraq's military had been dislodged from Kuwait but had not been sufficiently weakened to prevent Iraq from being a threat to its neighbors in the future.

Had the campaign focused initially on the liberation of Kuwait, the United States might have faced a difficult moment in which some of its allies might have resisted the decision to go after Saddam's war-making capability inside Iraq.

Officials at the State Department and the Pentagon had voiced concern that France or other members of the multinational coalition assembled to liberate Kuwait would try to limit U.S. actions against Iraqi territory. France is using its aircraft only in Kuwait, not against Iraq.

"There is an agreement in the coalition that the United Nations resolution does not permit a ceasefire until Kuwait is liberated. But there has not really been much discussion about that agreement, and it could be different when shooting starts," a U.S. official said hours before the war began Wednesday. But the concern that calls for a ceasefire would hamper the United States has lessened since then.

"I guess the United States is presenting us with a fait accompli," a key French official said Friday with a hint of irony in his voice. Last autumn he and other officials in Paris had argued that France would have to oppose American efforts to pursue Saddam's forces into Iraq once Kuwait was liberated. But Desert Storm has turned that sequence on its head. Instead of pounding the occupation army in Kuwait, American bombers are now pounding the five divisions of Iraq's elite Republican Guard anchored around the spot where the Iraqi, Kuwaiti and Saudi frontiers meet. In Kuwait, Pentagon briefers said last week, American aircraft are dropping one million leaflets urging surrender.

"This is both message and warfare," a Pentagon official said. "We want the Iraqi conscripts in Kuwait to understand that we are not hitting them first and hardest. We want them to see who we are hitting. And we want to destroy the Republican Guards' ability to become involved if we do have to cross the Saudi frontier."

"We will have a good idea in the next week or two of how the campaign is going to go and what the aftermath will look like," says Rep. Stephen J. Solarz, the New York Democrat who led the fight in the House for congressional approval of going to war against Iraq. "If the Republican Guard crumbles, I don't think the ground forces in Kuwait would be willing to fight to the last trench. Destroying the Republican Guard could even lead to a collapse of the regime in Baghdad. But we don't know that yet."

The Republican Guards are Saddam's Praetorian guard and his political base. By making them and Saddam's command and control apparatus priority targets, U.S. planners have committed themselves to breaking the military mainstays of Saddam's regime, even as Bush and Gen. Colin Powell, the head of the Joint Chiefs of Staff, assert that they have not specifically targeted Saddam himself.

Desert Storm will implicate the United States more deeply in the political aftermath of the war in Iraq than the administration appears willing to acknowledge or contemplate at this point.

That is, American actions, if successful, will bring a swift and sudden breakdown in the totalitarian system that has kept control over a nation rent by ethnic, religious and social conflicts. The danger of producing a greatly weakened Iraq is not that neighboring Syria and Iran will invade and break off parts of Iraq. The greater danger is that the Kurds, Shiites and others oppressed by Saddam's brutal regime will simultaneously rise up against the new, weakened central authority.

But conversations in recent weeks with U.S. officials, Iraqi dissident leaders and Arab officials strongly suggest that the United States is taking no active role in shaping the post-Saddam regime American actions are likely to produce.

That is being left instead to Saudi Arabia, which would undoubtedly like Saddam's successor to be a Sunni Moslem leader with enough power to control the Shiites and Kurds. According to one report from the region, the Saudis have sent messages to at least one military commander close to Saddam suggesting Riyadh would support him if Saddam is overthrown and the Kuwait occupation reversed.

Iran's leaders have told Turkish officials that all powers involved in the conflict -- presumably including the United States -- should work to produce "a non-threatening government" in Baghdad in which Iran would hope to have influence but not a dominating role. Syria reportedly takes the same attitude in its secret exchanges with the United States about the future. If Desert Storm does topple Saddam by ricochet, international peacekeeping forces may well have to be deployed in Iraq as well in Kuwait when the fighting stops. The United States and its allies are likely to take the lead in working out an international economic reconstruction plan for the two countries as well. President Bush foreshadowed such an approach Friday when he told reports, "When this is all over we want to be the healers" in the region.

But neither Bush nor his supporters feel that now is the time to concentrate on this aspect of the problem. "We have to defeat the enemy in front of us before we begin to worry about the aftermath," Solarz insists. "Saddam still thinks he can survive the air campaign and then endure through a land war. We have to show him that is not the case."

At week's end, a consensus had formed among senior American officials that Saddam's failure to respond effectively to the first three days of air war did not necessarily presage a short war, but represented instead Saddam's determination to fight a long war.

"At first we wondered if his failure to get any aircraft in the air or to have effective air defense represented a grand plan," a Pentagon official said Friday. "Now we think it is that he has an idea, not a very good idea, but one that he is going to follow. He will try to preserve his assets for the land war he wants to fight and to pull some Saddam surprises. He thinks we will pause and let him do that. That is why there will be no pause."

Jim Hoagland is associate editor and chief foreign correspondent for The Washington Post.