Since the terror attacks of September 11 2001, the Congressional Research Service (CRS) estimates that the United States has spent $1147 billion on going to wars. In terms of today’s dollars that makes the war on terrorism in Iraq, Afghanistan and on other operations such as those in the Philippines and the Horn of Africa, the second most expensive in the country’s history. Yet when the spending is converted into a share of US gross domestic product the spending comes in fifth behind the War of 1812, the Mexican War, Union spending in the Civil War, World War I, World War II, Korea and Vietnam.
The recently published CRS report Costs of Major US Warsattempts to compare war costs from the time of the American Revolution to the current day. Among the difficulties in doing so that it acknowledges is how to separate costs of military operations from costs of forces in peacetime. “In recent years,” the report says, “the DOD (Department of Defense) has tried to identify the additional ‘incremental’ expenses of engaging in military operations, over and above the costs of maintaining standing military forces.” The table below thus gives a figure estimating both “war” spending as a percentage of GDP in the peak year of each conflict and of total defence spending in the same year.