For post-World War II era defense spending, we used a historical table from the Office of Management and Budget -- http://www.whitehouse.gov/sites/default/files/omb/budget/fy2012/assets/hist03z1.xls -- and adjusted it for inflation using 1945 dollars using this calculator -- http://www.bls.gov/data/inflation_calculator.htm

Post-World War II
1945: $83 billion
1948: $7 billion
Spending decline: 92 percent

For the rest of the wars, we used a data set compiled by Todd Harrison of the Center for Strategic and Budgetary Assessments that includes inflation-adjusted defense spending from 1946 to 2012.

Post-Korea
1952: $484 billion
1955: $227 billion
Spending decline: 53 percent

Post-Vietnam
1968: $409 billion
1975: $302 billion
Spending decline: 26 percent

Post-Cold War
1987: $507 billion
1996: $364 billion
Spending decline: 28 percent

For worldwide troop levels, we turned to a data set -- http://thf_media.s3.amazonaws.com/2006/xls/troopMarch2005.xls -- produced by Tim Kane that covers the years 1950 to 2005. Kane compiled the numbers for the conservative Heritage Foundation and now is a senior fellow at the Ewing Marion Kauffman Foundation. We used the same criteria for picking the years, which in some cases resulted in different years being selected.

Post-Korea
1953: 3.56 million troops
1958: 2.60 million troops
Troop decline: 27 percent

Post-Vietnam
1968: 3.49 million troops
1978: 2.06 million troops
Troop decline: 40 percent

Post-Cold War
1987: 2.17 million troops
1996: 1.47 million troops
Troop decline: 32 percent