Defense expenditures amount to nearly 5 percent of US GDP -- well above the less than 2 percent of GDP spent by such allies as Canada, Germany and Britain. Analysts predict the US will have to cut military spending significantly in the next few years.
Cherie Cullen/U.S. Department of Defense/AP/File
There are related reasons: The US war effort in Iraq is winding down; President Obama may start pulling out of Afghanistan; NATO allies are moving to slash their military outlays. Most of all, budget cutters can't afford to ignore an area as vast as defense.
If budget deficits aren't seriously tackled, US spending on interest on the national debt will exceed its defense budget by fiscal 2018, says Todd Harrison, a senior fellow at the Center for Strategic and Budgetary Assessments. He predicts large defense cuts within three years.
It won't be easy. With 2.25 million full-time civilian and military personnel (not including part-time Guard and Reserve members) and thousands of contracts with firms, the Defense Department is a major economic engine for hundreds of communities and enjoys huge political clout.