Whereas recruits who join as officers tend to be upwardly-mobile, most enlisted personnel have a childhood background of relative socio-economic deprivation. For example, after the US suspended conscription in 1973, "the military disproportionately attracted African American men, men from lower-status socioeconomic backgrounds, men who had been in nonacademic high school programs, and men whose high school grades tended to be low".
A military or an armed force is a professional organization formally authorized by a sovereign state to use lethal or deadly force and weapons to support the interests of the state. It typically consists of branches such as an Army, Navy, Air Force, and in certain countries the Marines and Coast Guard. The task of the military is usually defined as defense of the state, and its citizens, and the prosecution of war against another state. The military may also have additional sanctioned and non-sanctioned functions within a society, including, the promotion of a political agenda, protecting corporate economic interests, internal population control, construction, emergency services, social ceremonies, and guarding important areas. The military may also function as a discrete subculture within a larger civil society, through the development of separate infrastructures, which may include housing, schools, utilities, logistics, health and medical, law, food production, finance and banking.
Having military intelligence representatives participate in the execution of the national defence policy is important, because it becomes the first respondent and commentator on the policy expected strategic goal, compared to the realities of identified threats. When the intelligence reporting is compared to the policy, it becomes possible for the national leadership to consider allocating resources over and above the officers and their subordinates military pay, and the expense of maintaining military facilities and military support services for them.
During World War I, the need to break the deadlock of trench warfare saw the rapid development of many new technologies, particularly tanks. Military aviation was extensively used, and bombers became decisive in many battles of World War II, which marked the most frantic period of weapons development in history. Many new designs, and concepts were used in combat, and all existing technologies of warfare were improved between 1939 and 1945.
There are two types of military history, although almost all texts have elements of both: descriptive history, that serves to chronicle conflicts without offering any statements about the causes, nature of conduct, the ending, and effects of a conflict; and analytical history, that seeks to offer statements about the causes, nature, ending, and aftermath of conflicts – as a means of deriving knowledge and understanding of conflicts as a whole, and prevent repetition of mistakes in future, to suggest better concepts or methods in employing forces, or to advocate the need for new technology.
Military tactics concerns itself with the methods for engaging and defeating the enemy in direct combat. Military tactics are usually used by units over hours or days, and are focused on the specific, close proximity tasks and objectives of squadrons, companies, battalions, regiments, brigades, and divisions, and their naval and air force equivalents.
Development of military doctrine is perhaps the more important of all capability development activities, because it determines how military forces were, and are used in conflicts, the concepts and methods used by the command to employ appropriately military skilled, armed and equipped personnel in achievement of the tangible goals and objectives of the war, campaign, battle, engagement, action or a duel. The line between strategy and tactics is not easily blurred, although deciding which is being discussed had sometimes been a matter of personal judgement by some commentators, and military historians. The use of forces at the level of organisation between strategic and tactical is called operational mobility.
Although mostly concerned with the military transport, as a means of delivery using different modes of transport; from military trucks, to container ships operating from permanent military base, it also involves creating field supply dumps at the rear of the combat zone, and even forward supply points in specific unit's Tactical Area of Responsibility.
By military department, $146.9 billion was allocated for the Department of the Army, $168.8 billion for the Department of the Navy, $161.8 billion for the Department of the Air Force and $102.8 billion for DoD-wide spending. By function, $138.6 billion was requested for personnel, $244.4 billion for operations and maintenance, $118.9 billion for procurement, $69.0 billion for research and development, $1.3 billion for revolving and management funds, $6.9 billion for military construction and $1.3 billion for family housing.
One difficult matter in the relation between military and society is control and transparency. In some countries, limited information on military operations and budgeting is accessible for the public. However transparency in the military sector is crucial to fight corruption. This showed the Government Defence Anti-corruption Index Transparency International UK published in 2013.
Note: While the U.S. Navy is older than the Marine Corps, the Marine Corps takes precedence due to previous inconsistencies in the Navy's birth date. The Marine Corps has recognized its observed birth date on a more consistent basis. The Second Continental Congress is considered to have established the Navy on 13 October 1775 by authorizing the purchase of ships, but did not actually pass the "Rules for the Regulation of the Navy of the United Colonies" until 27 November 1775. The Marine Corps was established by act of said Congress on 10 November 1775. The Navy did not officially recognize 13 October 1775 as its birth date until 1972, when then–Chief of Naval Operations Admiral Elmo Zumwalt authorized it to be observed as such.
The projected active duty end strength in the armed forces for fiscal year 2017 was 1,281,900 servicemembers, with an additional 801,200 people in the seven reserve components. It is an all-volunteer military, but conscription through the Selective Service System can be enacted at the President's request and Congress' approval. All males ages 18 through 25 who are living in the United States are required to register with the Selective Service for a potential future draft.
The human capital shortage may be worse than the shortage in ships. A report by the Maritime Administration to Congress highlighted the problem. The report “estimates that 11,768 qualified mariners ... are available to crew the Ready Reserve Force ... the estimated demand for mariners [in an emergency] is 13,607.” Given the shortage, those mariners who are available “may have to endure prolonged assignments or tours of duty until the emergency is over,” which will decrease effectiveness, increase errors and — of greatest concern — delay deploying the forces necessary to win a large-scale conflict.
During the war, significant advances were made in military communications through increased use of radio, military intelligence through use of the radar, and in military medicine through use of penicillin, while in the air, the guided missile, jet aircraft, and helicopters were seen for the first time. Perhaps the most infamous of all military technologies was the creation of the atomic bomb, although the exact effects of its radiation were unknown until the early 1950s. Far greater use of military vehicles had finally eliminated the cavalry from the military force structure.
In 1974, the first six women naval aviators earned their wings as Navy pilots. The Congressionally mandated prohibition on women in combat places limitations on the pilots' advancement, but at least two retired as captains. In 1989, Captain Linda L. Bray, 29, became the first woman to command American soldiers in battle during the invasion of Panama. The 1991 Gulf War proved to be the pivotal time for the role of women in the U.S. Armed Forces to come to the attention of the world media; there are many reports of women engaging enemy forces during the conflict.