Calculating the Pentagon's Base Budget
Using OMB's figure for total Defense Department (DoD) Spending (Function 051), we subtracted the Department of Defense's portion of the total FY2011 costs of the wars in Iraq and Afghanistan, based on figures provided by the Congressional Research Service. We then added back total war costs as calculated by NPP which include DoD costs as well as funding from other federal agencies – such as the State Department and the U.S. Agency for International Development (USAID) – that support the wars.
Before adding in NPP's war cost calculation, we subtracted an additional $30 billion from the Defense Department's FY2011 base budget. This is because while the $30 billion in "surge" funding for the additional 30,000 troops for Afghanistan announced by President Obama in December 2010 was appropriated in FY2010, it was authorized in FY2011. On NPP's cost of war calculations, it is correctly shown as being part of the FY2010 war funding level.
Sources
"Analytical Perspectives" from the Office of Management and Budget's "Budget of the U.S. Government, FY 2012," Table 32-1. "Budget Authority and Outlays by Function, Category, and Program"
"The Cost of Iraq, Afghanistan, and Other Global War on Terror Operations Since 9/11," Congressional Research Service report RL33110, March 29, 2011
NPP's Cost of War website