The United States Armed Forces are the Federal military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard. The history of the U.S. military dates to 1775, even before the Declaration of Independence marked the establishment of the United States. The Continental Army, Continental Navy, and Continental Marines were created in close succession by the Second Continental Congress in order to defend the new nation against the British Empire in the American Revolutionary War. The U.S. military budget accounts for approximately 40% of global arms spending. The United States and its close allies are responsible for 75% of the world's total military spending. The US also maintains the largest number of military bases on foreign soil across the world. US Army has over 9000 M1 Abrams main battle tanks. The United States Army (USA) is the largest branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services. The Regular Army reported a strength of 546,057 soldiers; the Army National Guard (ARNG) reported 358,078 and the United States Army Reserve (USAR) reported 201,166 putting the combined component strength total at 1,105,301 soldiers. After the September 11 attacks, and as part of the Global War on Terror, U.S. and NATO forces invaded Afghanistan in 2001, displacing the Taliban government. The United States Army Special Operations Command (Airborne) (USASOC) is the command charged with overseeing the various special operations forces of the United States Army and is the largest component of the United States Special Operations Command. Its mission is to organize, train, educate, man, equip, fund, administer, mobilize, deploy and sustain Army special operations forces to successfully conduct worldwide special operations. The United States Army Special Forces, known as the Green Berets because of their distinctive service headgear, are a special operations force tasked with five primary missions: unconventional warfare (the original and most important mission of Special Forces), foreign internal defense, special reconnaissance, direct action, and counter-terrorism The United States Navy (USN) is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. It was estimated to be larger than the next 13 largest navies combined in terms of battle fleet tonnage in 2009. The U.S. Navy also has the world's largest aircraft carrier fleet, with ten in service, two under construction, eight more planned, and two in active reserve. The service has 317,054 personnel on active duty and 109,671 in the Navy Reserve. It operates 290 ships in active service and more than 3,700 aircraft. The United States Navy has six active numbered fleets â€“ Third, Fifth, Sixth, Seventh Fleet and Tenth Fleets are each led by a three-star vice admiral, and the Fourth Fleet is led by a rear admiral. These six fleets are further grouped under Fleet Forces Command (the former Atlantic Fleet), Pacific Fleet, Naval Forces Europe-Africa, and Naval Forces Central Command, whose commander also doubles as Commander Fifth Fleet; the first three commands being led by four-star admirals. As of 2013, the navy operates 283 ships, 3,659 aircraft, 50,000 non-combat vehicles and owns 75,200 buildings on 3,300,000 acres (13,000 km2). In addition, the Navy has 122 ships operated by the Military Sealift Command (MSC) crewed by a combination of civilian contractors and a small number of uniformed Naval personnel. The navy had established a minimum requirement for 11 aircraft carriers, but dropped to 10 when Enterprise was retired in December 2012, before Gerald R. Ford enters service. A carrier is typically deployed along with a host of additional vessels, forming a carrier strike group. The supporting ships, which usually include three or four Aegis-equipped cruisers and destroyers, a frigate, and two attack submarines, are tasked with protecting the carrier from air, missile, sea, and undersea threats as well as providing additional strike capabilities themselves. Ready logistics support for the group is provided by a combined ammunition, oiler, and supply ship. Amphibious assault ships are the centerpieces of US amphibious warfare and fulfill the same power projection role as aircraft carriers except that their striking force centers on land forces instead of aircraft. Carrier strike groups comprise a principal element of U.S. power projection capability. Previously referred to as Carrier Battle Groups (a term still used by other nations), they are often referred to by the carrier they are associated with (e.g., Enterprise Strike Group). There are currently 11 carrier strike groups: five based on the West Coast, five based on the East Coast, and one forward-deployed to NS Yokosuka, Japan. The United States Marine Corps (USMC) is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the U.S. Navy to rapidly deliver combined-arms task forces. The U.S. Marine Corps is one of the four branches in the U.S. Department of Defence as well as one of the seven uniformed services of the United States. It operates posts on land and aboard sea-going amphibious warfare ships around the world. The Marine Corps has been a component of the U.S. Department of the Navy since 1834, working closely with naval forces for training, transportation, and logistics. By the mid-20th century, the Marine Corps had become a major theorist and the dominant practitioner of amphibious warfare. Its ability to rapidly respond on short notice to expeditionary crises gives it a strong role in the implementation and execution of American foreign policy. The U.S. Marine Corps has around 194,000 active duty members and just under 40,000 reserve Marines as of 2010. It is the smallest of the United States Armed Forces in the U.S. Department of Defense. The organic aviation capability of the Marine Corps is essential to its mission. The Corps operates both rotary-wing and fixed-wing aircraft mainly to provide assault support and close air support to its ground forces. However, other aircraft types are also used in a variety of support and special-purpose roles. The United States Air Force (USAF) is the aerial warfare service branch of the United States Armed Forces and one of the seven American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947. It is the most recent branch of the U.S. military to be formed, and is the largest and one of the world's most technologically advanced air forces. The USAF articulates its core functions as Nuclear Deterrence Operations, Special Operations, Air Superiority, Global Integrated ISR, Space Superiority, Command and Control, Cyberspace Superiority, Personnel Recovery, Global Precision Attack, Building Partnerships, Rapid Global Mobility and Agile Combat Support. The U.S. Air Force provides air support for surface forces and aids in the recovery of troops in the field. As of 2014, the service operates more than 5,638 aircraft (162 heavy bombers, 480 tanker aircraft, 930 transport aircraft, 85 electronic-warfare aircraft, 1600 fighter aircraft, and others), 450 ICBMs and 63 satellites. It has a $140 billion budget with 332,854 active personnel, 185,522 civilian personnel, 71,400 reserve personnel, and 106,700 air guard personnel. The United States Coast Guard (USCG) is a branch of the United States Armed Forces and one of the country's seven uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the U.S. military branches for having a maritime law enforcement mission (with jurisdiction in both domestic and international waters) and a federal regulatory agency mission as part of its mission set. It operates under the U.S. Department of Homeland Security during peacetime, and can be transferred to the U.S. Department of the Navy by the U.S. President at any time, or by the U.S. Congress during times of war. As one of the country's five armed services, the Coast Guard has been involved in every war from 1790 up to the Iraq War and the War in Afghanistan. As of 2012 the Coast Guard had approximately 42,000 men and women on active duty, 7,900 reservists, 32,000 auxiliarists, and 8,700 full-time civilian employees. In terms of size, the U.S. Coast Guard by itself is the world's 12th largest naval force. The Coast Guard operates approximately 204 fixed and rotary wing aircraft from 24 Coast Guard Air Stations throughout the contiguous United States, Alaska, Hawaii, and Puerto Rico.