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.