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.
In this photo provided by the U.S. Department of Defense, Defense Secretary Robert Gates speak with US Army Majors at the Command and General Staff College at Ft. Leavenworth, Kansas on May 7. Gates has stepped up his campaign shift Pentagon spending priorities. Large cuts in defense spending are likely considering the country's ballooning national deficit.
Cherie Cullen/U.S. Department of Defense/AP/File
It's bigger than Wal-Mart, employs more people than the United States Post Office, and far outspends all its competitors.
It's the US Department of Defense. Next year, though, budget cutters in Congress and the White House will probably begin cutting it down to size in order to slash America's outsize budget deficit.
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.
The need for serious deficit reduction and a loss of political support for high defense spending make cuts inevitable, says Gordon Adams, a defense expert at American University.
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.