After World War II, with the onset of the Cold War, the constant technological development of new weapons was institutionalised, as participants engaged in a constant 'arms race' in capability development. This constant state of weapons development continues into the present, and remains a constant drain on national resources, which some[who?] blame on the military-industrial complex.
Since then, the advances made by human societies, and that of weapons, has been irretrievably linked. Stone weapons gave way to Bronze Age weapons, and later, the Iron Age weapons. With each technological change, was realised some tangible increase in military capability, such as through greater effectiveness of a sharper edge in defeating leather armour, or improved density of materials used in manufacture of weapons.
Prospective service members are often recruited from high school or college, the target age ranges being 18–35 in the Army, 18–28 in the Marine Corps, 18–34 in the Navy, 18–39 in the Air Force and 18–27 (up to age 32 if qualified for attending guaranteed "A" school) in the Coast Guard. With the permission of a parent or guardian, applicants can enlist at age 17 and participate in the Delayed Entry Program (DEP), in which the applicant is given the opportunity to participate in locally sponsored military activities, which can range from sports to competitions led by recruiters or other military liaisons (each recruiting station's DEP varies).
As of 31 December 2010, U.S. Armed Forces troops were stationed in 150 countries; the number of non-contingent deployments per country ranges from 1 in Suriname to over 50,000 in Germany. Some of the largest deployments are: 103,700 in Afghanistan, 52,440 in Germany (see list), 35,688 in Japan (USFJ), 28,500 in South Korea (USFK), 9,660 in Italy and 9,015 in the United Kingdom. These numbers change frequently due to the regular recall and deployment of units.
Alongside this, World War II also inspired films as varied as The Dam Busters, 633 Squadron, Bridge on the River Kwai, The Longest Day, Catch-22, Saving Private Ryan, and The Sea Shall Not Have Them. The next major event, the Korean War inspired a long-running television series M*A*S*H. With the Vietnam War, the tide of balance turned, and its films, notably Apocalypse Now, Good Morning, Vietnam, Go Tell the Spartans, Born on the Fourth of July, and We Were Soldiers, have tended to contain critical messages.
The obligations of military employment are many. Full-time military employment normally requires a minimum period of service of several years; between two and six years is typical of armed forces in Australia, the UK and the US, for example, depending on role, branch, and rank. Some armed forces allow a short discharge window, normally during training, when recruits may leave the armed force as of right. Alternatively, part-time military employment, known as reserve service, allows a recruit to maintain a civilian job while training under military discipline at weekends; he or she may be called out to deploy on operations to supplement the full-time personnel complement. After leaving the armed forces, recruits may remain liable for compulsory return to full-time military employment in order to train or deploy on operations.
All of the branches work together during operations and joint missions in Unified Combatant Commands, under the authority of the Secretary of Defense with the typical exception of the Coast Guard. Each of the Unified Combatant Commands is headed by a Combatant Commander, a senior commissioned officer who exercises supreme command authority per 10 U.S.C. § 164 over all of the forces, regardless of branch, within his geographical or functional command. By statute, the chain of command flows from the President to the Secretary of Defense to each of the Combatant Commanders. In practice, the Chairman of the Joint Chiefs of Staff often acts as an intermediary between the Secretary of Defense and the Combatant Commanders.
With very few exceptions, becoming a non-commissioned officer (NCO) or petty officer in the U.S. Armed Forces is accomplished by progression through the lower enlisted ranks. However, unlike promotion through the lower enlisted tier, promotion to NCO is generally competitive. NCO ranks begin at E-4 or E-5, depending upon service and are generally attained between three and six years of service. Junior NCOs function as first-line supervisors and squad leaders, training the junior enlisted in their duties and guiding their career advancement.
Your ASVAB scores determine what jobs you will qualify for in the military. But before you embarrass yourself in front of active duty service members, know that a job in the Army and the Marine Corps is called an MOS, which is an acronym for Military Occupational Specialty. In the Air Force, jobs are called AFSC – Air Force Specialty Code. In the Navy they are known as an NEC - Navy Enlisted Classification and the Coast Guard, jobs are called ratings, or rate for short.