The development of breech loading had the greatest effect on naval warfare, for the first time since the Middle Ages, altering the way weapons are mounted on warships, and therefore naval tactics, now divorced from the reliance on sails with the invention of the internal combustion. A further advance in military naval technology was the design of the submarine, and its weapon, the torpedo.
To coordinate military strategy with political affairs, the President has a National Security Council headed by the National Security Advisor. The collective body has only advisory power to the President, but several of the members who statutorily comprise the council (the Secretary of State, the Secretary of Energy and the Secretary of Defense) possess executive authority over their own departments.
The military organization is characterized by a strict hierarchy divided by military rank, with ranks normally grouped (in descending order of authority) as officers (e.g. Colonel), non-commissioned officers (e.g. Sergeant), and personnel at the lowest rank (e.g. Private Soldier). While senior officers make strategic decisions, subordinated military personnel (soldiers, sailors, marines, or airmen) fulfil them. Although rank titles vary by military branch and country, the rank hierarchy is common to all state armed forces worldwide.
Limited Duty Officer: due to the highly technical nature of some officer billets, the Marine Corps, Navy and Coast Guard employ a system of promoting proven senior enlisted members to the ranks of commissioned officers. They fill a need that is similar to, but distinct from that filled by warrant officers (to the point where their accession is through the same school). While warrant officers remain technical experts, LDOs take on the role of a generalist, like that of officers commissioned through more traditional sources. LDOs are limited, not by their authority, but by the types of billets they are allowed to fill. However, in recent times they have come to be used more and more like their more-traditional counterparts.
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.
After enlistment, new recruits undergo basic training (also known as "boot camp" in the Marine Corps, Navy and Coast Guard), followed by schooling in their primary Military Occupational Specialty (MOS), rating and Air Force Specialty Code (AFSC) at any of the numerous training facilities around the United States. Each branch conducts basic training differently. The Marine Corps send all non-infantry MOS's to an infantry skills course known as Marine Combat Training prior to their technical schools. Air Force Basic Military Training graduates attend Technical Training and are awarded their Air Force Specialty Code (AFSC) at the apprentice (3) skill level. All Army recruits undergo Basic Combat Training (BCT), followed by Advanced Individual Training (AIT), with the exceptions of cavalry scouts, infantry, armor, combat engineers and military police recruits who go to One Station Unit Training (OSUT), which combines BCT and AIT. The Navy sends its recruits to Recruit Training and then to "A" schools to earn a rating. The Coast Guard's recruits attend basic training and follow with an "A" school to earn a rating.
Under the Montgomery GI Bill, the Army, Navy, Air Force, Marine Corps and Coast Guard (and their Reserves and the National Guard) provide a cash education incentive to encourage you to join and serve a tour of duty. The Montgomery GI Bill (MGIB) provides up to 36 months of education benefits to eligible veterans for college, business, technical or vocational courses, correspondence courses, apprenticeship/job training and flight training. MGIB benefits may be used while on active duty or after a fully honorable discharge from active duty.
In exchange for a service commitment, the Reserve Officers' Training Corps (ROTC) program provides you with money for college while you're in school. You must take one military science course along with your other college courses and, upon graduation, enter the service as a commissioned officer. (There is no military commitment for the first year in ROTC, allowing you to pursue ROTC on a trial basis to see if ROTC is for you.) Full ROTC scholarships pay for almost all tuition, fees and books charges for four years of college. ROTC scholarships also come in one, two and three-year lengths. For more information, call 1-800-USA-ROTC (Army), 1-800-USA-NAVY (Navy), 1-866-423-7682 (Air Force) and 1-800-MARINES (Marines).
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.
From the time of its inception, the U.S. Armed Forces played a decisive role in the history of the United States. A sense of national unity and identity was forged as a result of victory in the First Barbary War and the Second Barbary War. Even so, the founders of the United States were suspicious of a permanent military force. It played a critical role in the American Civil War, continuing to serve as the armed forces of the United States, although a number of its officers resigned to join the military of the Confederate States. The National Security Act of 1947, adopted following World War II and during the Cold War's onset, created the modern U.S. military framework. The Act established the National Military Establishment, headed by the Secretary of Defense; and created the Department of the Air Force and the National Security Council. It was amended in 1949, renaming the National Military Establishment the Department of Defense, and merged the cabinet-level Department of the Army, Department of the Navy, and Department of the Air Force, into the Department of Defense.
The First World War was also responsible for a new kind of military depiction, through poetry. Hitherto, poetry had been used mostly to glorify or sanctify war. The Charge of the Light Brigade by Alfred, Lord Tennyson, with its galloping hoofbeat rhythm, is a prime late Victorian example of this, though Rudyard Kipling had written a scathing reply, The Last of the Light Brigade, criticising the poverty in which many Light Brigade veterans found themselves in old age. Instead, the new wave of poetry, from the war poets, was written from the point of view of the disenchanted trench soldier.
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.