The United States will head up the occupation and reconstruction of Iraq with perhaps some 200,000 troops and civilian advisors in the first few months after the war. Their task will be daunting -- to rebuild a war-torn country that has been brutalized by decades of Saddam Hussein's dictatorship.

Before the war, about two-thirds of Iraq's people depended on foreign food aid. And international relief agencies say that the most pressing concern after the war will be ensuring that the country's humanitarian needs are met.

Former Clinton administration Pentagon spokesman Kenneth Bacon is President of Refugees International -- a humanitarian advocacy group based here in Washington. He warns that the Iraqi food and refugee crisis could be severe.

"Depending on the length of the conflict, there could be massive displacement in Iraq. The UN estimates that displacement could total 20% of the Iraqi population. That is about five million people, if the war lasts two or three months. If the war were to last that long, there could also be massive food shortages within the country and massive needs for medicine,? he says.

?If it's a short war, then I think there may not be a demanding humanitarian crisis,? Mr. Bacon says. ?There won't be a lot of displacement. There will be some, but not as much as the U-N has projected. The food pipeline which is under the UN Oil-for-Food Program will have been interrupted but not broken, so food supplies can restart pretty quickly. And most people in Iraq probably have a month-to-six weeks worth of food already stockpiled. So they do have some capacity.?

?If there is a short war, there probably won't be a humanitarian crisis and the U.S. will have calculated correctly that it didn't need to stockpile massive amounts of food," Mr. Bacon said.

Michael O'Hanlon is a Senior Foreign Policy Analyst at The Brookings Institution here in Washington. He says that despite the pre-war posturing in the United Nations Security Council, the UN will likely play a key role in post-war relief efforts.

?The UN has the ability to distribute food and so forth. But we [the United States] will have to provide the security," he says. ?I think you have to view the humanitarian relief as a multidimensional operation. And a lot of the problem is going to be getting to the people who need the food with security, and that will not be within the auspices of the UN humanitarian agencies.?

?So I think, you'll see some teamwork -- UN, private non-governmental organizations and perhaps some U.S. governmental organizations providing relief and the U.S. military helping to cart around supplies, but most of all, providing security," he says.

Regardless of the duration and severity of the conflict, most analysts believe that the initial humanitarian crisis in Iraq should be over within six months of the war's end. But they caution that the prospect of ethnic and sectarian violence among Iraq's three main factions -- Shiites, Sunnis and Kurds -- will be one of the greatest challenges in rebuilding the country. And observers warn that conflict among these groups could add to the humanitarian crisis. That's what the allied coalition is hoping to avoid.

Michael O'Hanlon of The Brookings Institution compares the situation to U.S. democracy building efforts in the Balkans.

"We've been in Bosnia for seven-and-a-half years now. On the one hand, we have had a more intense civil war than the crisis in Iraq. On the other hand, it's the same sort of thing as Iraq -- three major ethnic groups with an unhappy history of getting along,? he says. ?And I think you have to go in and assume that it's going to be just as tough in Iraq, at least for a while. And you have to build a whole new political class before this country is ready to go on its own."

John Hulsman is a Senior Foreign Policy Analyst at The Heritage Foundation here in Washington. He says the Bush Administration should learn from mistakes made by the Clinton Administration.

?I think if you look at what has gone wrong in areas such as Kosovo and Bosnia, despite the best intentions of the world, two mistakes were made,? he says. ?One, it wasn't made clear who was in charge of what exactly. There was a lot of overlapping authority rather than clear and linear authority, so there were turf battles; there were political battles. And as a result, the efforts were incoherent.?

?The second thing is more philosophical,? Mr. Hulsman says. ?I think the top-down nation building approach the Clinton administration adopted has proven to have failed utterly in Haiti, Somalia, Bosnia, Kosovo, etc. And the only approach that's really going to work is to very quickly indigeonize the process, to involve the Iraqis as quickly as possible in their own governance, because only when they become stakeholders in that kind of situation is it likely to be self-sustaining. So I think that philosophically, we need to work with the units of politics in the country, which are the ethnic groups -- the Sunnis, the Shias and the Kurds -- and from there work up rather than set utopian goals that you don't meet."

Most analysts warn that decades of tyranny under Saddam Hussein means that a return to the rule of law in Iraq won't be easy. And because the Iraqi dictator has staffed the country's bureaucracy with loyalists, an allied rebuilding effort will have to include a major restructuring of Iraq's governmental institutions.

The Heritage Foundation?s John Hulsman says some aspects of the rebuilding of Iraq can be modeled on aspects of the rebuilding of Afghanistan.

"It has been pretty clear that they [the allies] want to turn over the domestic aspects of this thing to the Iraqis as quickly as possible -- first to a consultative assembly similar to the Loya Jirga in Afghanistan and then from that group you could distill down an actual governing board,? Mr. Hulsman says.

?And remember, the Iraqis are a people who have very talented administrators. There are people there who can run things. I think that will actually happen fairly quickly,? he says. ?But I think that on the 'power ministry' front -- meaning the Interior Ministry, the Army, the Police, the National Guard, this kind of thing -- that is a much longer process where the United States is going to need to retain direct control and eradicate the Baathist Party members in these groups who supported Saddam Hussein and his obscene atrocities."

Gordon Adams, Director of Security Policy Studies at George Washington University, says reestablishing free and fair courts will be crucial to the rebuilding of Iraq.

"One of the big jobs the United States and any international partners will face is bringing in justice, policing and a tribunal," he says. ?There's going to have to be a decision about war crimes and how deeply those should be pursued. And that's going to be an important decision for the Iraqi people, to make sure that former leaders who have been responsible for crimes against the people of Iraq are prosecuted. So you are going to have to bring in some outside judicial presence. You're certainly going to have to bring in outside police and retrain the Iraqi police. And you're going to have to create some kind of tribunal."

There's near universal agreement that the cost of rebuilding Iraq will be enormous. Estimates range from $25 to more than $100 billion. Humanitarian aid in the first few years alone may total $3 or $4 billion. Governance costs could run from $10 to $15 billion. Repairing the country's infrastructure -- roads, schools, hospitals, water treatment facilities and electric power plants, for example -- could exceed $30 billion.

George Washington University's Gordon Adams says much of this depends on how hard the Iraqi regime fights to stay in power.

?If Saddam Hussein decides to destroy his oil fields as part of a scorched earth policy, if he decides to blow up his own bridges, if he decides to destroy buildings himself -- all of that will have to be reconstructed,? Professor Adams says. ?If aerial bombardments, and artillery and tank poundings take out electric power grids or oil production and refining capabilities during the war, that will have to be reconstructed.?

?In part, the problem is hard to figure because it will depend on how much damage is done in the war itself,? he says. ?We know Iraq has an extensive infrastructure that has to be upgraded. The biggest problem they will have will be with their oil infrastructure. If it's not damaged by the war, their oil infrastructure still will require $5, $10 or $15 billion worth of investment just to bring it up to 1991 levels. It has been degraded very badly through inattention and lack of investment."

Turning around Iraq's oil industry will be crucial in reviving the country's economy and in helping to pay for Iraq's reconstruction. And that could take years. But in the long run, analysts say, forging an inclusive, representative government in Baghdad will be the ultimate test in rebuilding Iraq.