What is the cost of the war in Iraq? (The Times of London Editorial)

The Bush Administration was wrong about the benefits of the war and it was wrong about the costs of the war. The president and his advisers expected a quick, inexpensive conflict. Instead, we have a war that is costing more than anyone could have imagined.
The cost of direct US military operations -- not even including long-term costs such as taking care of wounded veterans -- already exceeds the cost of the 12-year war in Vietnam and is more than double the cost of the Korean War.
And, even in the best case scenario, these costs are projected to be almost ten times the cost of the first Gulf War, almost a third more than the cost of the Vietnam War, and twice that of the First World War. The only war in our history which cost more was the Second World War, when 16.3 million U.S. troops fought in a campaign lasting four years, at a total cost (in 2007 dollars, after adjusting for inflation) of about $5 trillion. With virtually the entire armed forces committed to fighting the Germans and Japanese, the cost per troop (in today's dollars) was less than $100,000 in 2007 dollars. By contrast, the Iraq war is costing upward of $400,000 per troop.