May 17, 2018 The Fiscal Times
A nonpartisan analysis from the Stimson Center found that the U.S. has spent roughly $2.8 trillion fighting terrorism since Sept. 11, 2001. This article contrasts the Stimson Center figures with the Watson Institute's, which estimates that all war-related spending since 9/11, coupled with future obligations, totals $5.6 trillion.
What the War on Terror Has Cost Since 9/11 (Costs of War mentioned) – The Fiscal Times