Congress is also pressing the administration on the costs of reconstruction and building democracy in Iraq and the region. The uncertainties in both these ventures make estimates precarious.
While defense analysts can calculate the cost of a Tomahawk cruise missile ($1 million), it's more difficult to assign numbers to reconstruction and democracy-building. The president's current supplemental request only includes up to $3.4 billion for reconstruction and humanitarian assistance, but experts say those nonmilitary costs could range from a low end of $25 billion to at least $135 billion over the next five years.
"Anytime you have underlying debates about such assumptions, you can't do meaningful financial or budgetary analysis," says Steven Kosiak, director of budget studies for the Center for Strategic and Budgetary Assessments, a Washington-based think tank. "Some people are surprised by the range of estimates, but it just reflects the underlying reality."
Experts are also struggling with how to factor in costs to the US economy of unanticipated consequences of a long presence in Iraq, including a shift in oil prices. While some administration spokesmen have suggested the price of oil could quickly drop to $20 a barrel in a post-Saddam Hussein Iraq, others say that a disruption in supplies or an Arab oil boycott could cost the US economy more than the war.
"The mere threat of war has already raised the cost of oil used in the American economy by nearly $100 billion a year," says Sen. Edward Kennedy (D) of Massachusetts.
In the run-up to this week's debate, key administration officials are circulating several estimates to ease concerns. These include: