History: United States Of America, 1940

Military service is voluntary, though conscription may occur in wartime through the Selective Service System. American forces can be rapidly deployed by the Air Force's large fleet of transport aircraft, the Navy's eleven active aircraft carriers, and Marine Expeditionary Units at sea with the Navy's Atlantic and Pacific fleets. The military operates 865 bases and facilities abroad, and maintains deployments greater than 100 active duty personnel in 25 foreign countries. The extent of this global military presence has prompted some scholars to describe the United States as maintaining an "empire of bases."
Total U.S. military spending in 2008, more than $600 billion, was over 41% of global military spending and greater than the next fourteen largest national military expenditures combined. The per capita spending of $1,967 was about nine times the world average; at 4% of GDP, the rate was the second-highest among the top fifteen military spenders, after Saudi Arabia. The proposed base Department of Defense budget for 2011, $549 billion, is a 3.4% increase over 2010 and 85% higher than in 2001; an additional $159 billion is proposed for the military campaigns in Iraq and Afghanistan. As of September 2010, the United States is scheduled to have 96,000 troops deployed to Afghanistan, and 50,000 to Iraq. As of January 5, 2011, the United States had suffered 4,432 military fatalities during the Iraq War, and 1,448 during the War in Afghanistan.