One estimate of the military pricetag: $5 billion each month.
Fighting in Iraq has been prolonged and remains intense enough that it has pushed the total cost of US military operations since Sept. 11, 2001, close to that of the Korean War.
Despite the yawning federal deficit, Congress hasn't blinked at this price. And while annual defense spending is now as high as it ever was during the Reagan buildup, the US economy as a whole is much larger, making it easier, in economic terms, for the nation to shoulder the bill.
Yet the costs for Pentagon operations are likely to pile up in years ahead. By 2010, war expenses might total $600 billion, according to the Congressional Budget Office. Much depends on when - and how many - US military personnel can be withdrawn from the Iraqi theater of operations.
"We can't be any more certain about the trend of the defense budget than we can be about the number of troops that will be deployed overseas," says Steven Kosiak, director of budget studies for the Center for Strategic and Budgetary Assessments.
The demands and unpredictability of war have, in essence, turned the defense budget into a two-part allocation. First is the regular budget request, which contains acquisition and research and development funds as well as personnel and operations costs, and which Congress considers in its normal appropriations process. Second is the supplemental appropriations - the add-on emergency spending requested by the administration later in the year.
Congress gave final passage to a 2005 supplemental defense bill just last week. Of the $82 billion contained in the bill, all but $76 billion will pay for Defense Department operations costs. The cost of the US military in Iraq is running about $5 billion a month, estimated the former Pentagon comptroller earlier this year.