The costs of a war in Iraq could be dwarfed by the costs of peace - especially if America's occupation of Iraq is prolonged, economists say.

While President Bush has clearly laid out the prospects of a war in Iraq and the risks involved, the administration has been less forthcoming on what would happen to Iraq after American tanks sweep into Baghdad, who will control Iraq's lucrative oil fields and what government will replace Saddam's one-man rule.

Estimates of the costs of an occupation of Iraq vary wildly, depending on how many troops are used and how long they remain. The Congressional Budget Office forecasts it could require from 70,000 to 200,000 U.S. troops to occupy Iraq, a country the size of California, at a cost that ranges between $12 billion to $48 billion a year.

Other analysts say the costs could easily be more if U.S. troops have to deal with a post-Saddam humanitarian crisis that would involve housing and feeding refugees left homeless by the war, or cleaning up sites made toxic by chemical weapons.

Those costs could pale in contrast to the war itself. Congressional estimates put the cost of a short and successful war of two months between $49 billion and $60 billion. The 1991 Persian Gulf War cost $61 billion, most of it paid by allies.

The Pentagon is putting together a supplemental spending package that seeks approval from Congress for an additional $95 billion to pay this year's costs for the Iraqi conflict, the occupation and aspects of the war on terrorism. A breakdown in those costs was not available, but the total amount is about the same as what the entire U.S. federal government spent in 1961.

Sen. Joseph Biden of Delaware, ranking Democrat on the Senate Foreign Relations Committee, estimates that American forces will need to occupy Iraq for at least five years - the military governor will have to remove 50,000 security forces loyal to Saddam from their government posts and replace other Saddam loyalists in the government.

He estimates that the post-war occupation phase will cost U.S. taxpayers at least $20 billion a year. "It will be costly, and I might add, it's not included in the president's budget. But it will have to come from somewhere."

Using Iraq's oil revenues to rebuild the country could cover some of these costs. Applying Iraq's oil production of 3 million gallons a day would produce at least $25 billion a year, but Iraq needs most of those funds to buy food and other necessities the country does not produce itself.

Bringing Iraq's oil production back to its pre-1991 level of 6 million gallons a day would require investments to buy new machinery and would take several years to complete. A United Nations report estimates the effort would require $22 billion.

Yale University economist William Nordhaus scoffs at the notion Iraqi oil could be used to pay for the costs of the occupation. He notes that western businesses already have $78 billion in claims filed against Iraq for unpaid contracts, and an additional $300 billion in damage claims were filed against Iraq in the wake of the Persian Gulf War. The country's other natural resource is phosphates, used to make soap.

"Given all these claims, to divert funds from vital necessities to pay the expenses of the U.S. occupation forces would be economic and political folly," Nordhaus says. Nordhaus also doubted foreign countries would offer to pick up the costs unless there is broad support for military action endorsed by the United Nations. The coalition allies covered 90 percent of the $61 billion in costs of the Persian Gulf War.

Also left unanswered is who would govern Iraq.

Iraqi opposition leaders are openly fighting one Pentagon plan floated this month calling for putting Iraq under control of an American military governor, with U.S. military officers in charge of the major ministries for at least one year. The plan is similar to the way the United States governed Germany after World War II.

The anti-Saddam Iraqi National Congress protests that the occupation plan would permit lower-level bureaucrats who are loyal members of Saddam's Ba'ath Socialist Party to keep their government jobs. They say that violates an agreement reached at a London conference last year that promised the exiled opposition would get the Baghdad government.

Nor is it clear how long the American occupation might last. President Bush says that after the fighting subsides, "the United States and our allies will help the Iraqi people rebuild their economy, and create the institutions of liberty in a unified Iraq at peace with its neighbors."

That could be a daunting task. Iraq has no history of democratic institutions, and has major populations of Kurds and Shiite and Sunni Muslims to keep from feuding.

Brookings Institution analysts Philip Gordon and Michael O'Hanlon note that NATO deployed 50,000 peacekeeping troops in Bosnia at a cost of $10 billion a year in 1996, and still maintains 20,000 troops there.

"The United States would need to lead a major international effort to help form a stable national government. Such an effort could require a multi-year military presence by tens of thousands of U.S. military forces," they say.

U.S. taxpayers would pick up other costs associated with the war, including the economic aid Turkey is demanding as well as debt forgiveness, and increased assistance for Jordan.