Costs of Major U.S. Wars and Recent U.S. Overseas Military Operations [Updated October 3, 2001] [open pdf - 51KB]
"The direct costs of U.S. military operations have varied greatly, with a high of some $4.7 trillion (in constant FY2002 dollars) for the incremental costs of World War II, to a few million per operation for U.S. peacekeeping efforts in Cambodia, Angola, and the Western Sahara. The incremental military costs of the war in Vietnam to the United States was $572 billion in FY2002 dollars, and the Persian Gulf War incremental costs totaled some $80 billion in FY2002 dollars, most of which was covered by allied contributions. For the decade after the war, from FY1991 through FY2000, the DOD has incurred some $9.2 billion in incremental costs (in FY2002 dollars) performing peacekeeping and related security missions in Southwest Asia, i.e., in and around Iraq. For the same period, the incremental costs of DOD peacekeeping and related operations in the Balkans was $17 billion in constant FY2002 dollars. The total of U.S. military costs for peacekeeping and related security efforts over that decade was $29.6 billion in FY2002 dollars."
CRS Report for Congress, RS21013