The following table shows spending in 2009 dollars (i.e. controlled for inflation) of national defense spending since 1940. National defense is a category of spending defined by the government. It includes the Department of Defense, nuclear weapons and other military-related spending. However, it does not include military assistance or veterans' benefits.
Source: Office of Management and Budget, Budget of the U.S. Government, FY2009, Historical Tables [1].
Links:
[1] http://www.whitehouse.gov/omb/budget