Later this became known as military science, and later still, would adopt the scientific method approach to the conduct of military operations under the influence of the Industrial Revolution thinking. In his seminal book On War, the Prussian Major-General and leading expert on modern military strategy, Carl von Clausewitz defined military strategy as 'the employment of battles to gain the end of war'.[34] According to Clausewitz:

On 3 December 2015, U.S. Defense Secretary Ashton Carter announced that all military combat jobs would become available to women.[38] This gave women access to the roughly 10% of military jobs which were previously closed off due to their combat nature.[39] The decision gave military services until January 2016 to seek exceptions to the rule if they believe that certain jobs, such as machine gunners, should be restricted to men only.[40] These restrictions were due in part to prior studies which stated that mixed gender units are less capable in combat.[41] Physical requirements for all jobs remained unchanged, though.[41] Many women believe this will allow for them to improve their positions in the military, since most high-ranking officers start in combat positions. Since women are now available to work in any position in the military, female entry into the draft has been proposed.[42]

The first step that one will take after deciding to pursue a career in the military is taking the Armed Service Vocational Aptitude Battery test. This is more commonly referred to as the ASVAB. The ASVAB not only determines whether or not a candidate is qualified to serve in the armed forces but also shows which specific job they have the most aptitude for.

Under current Department of Defense regulation, the various components of the U.S. Armed Forces have a set order of seniority. Examples of the use of this system include the display of service flags, placement of Soldiers, Marines, Sailors, Airmen and Coast Guardsmen in formation, etc. When the Coast Guard shall operate as part of the Department of the Navy, United States Coast Guard Academy cadets, the United States Coast Guard and the Coast Guard Reserve shall take precedence after United States Naval Academy midshipmen; the United States Navy; and Navy Reserve, respectively.[49]
Jump up ^ The United States Coast Guard has both military and law enforcement functions. Title 14 of the United States Code provides that "The Coast Guard as established 28 January 1915, shall be a military service and a branch of the armed forces of the United States at all times." Coast Guard units, or ships of its predecessor service, the Revenue Cutter Service, have seen combat in every war and armed conflict of the United States since 1790, including the Iraq War.

After the final ability estimate is computed, it is converted to a standard score on the ASVAB score scale that has been statistically linked to the ability estimate through a process called equating. Equating studies are conducted for every paper and pencil ASVAB form to ensure that scores have the same meaning regardless of which test form the examinee receives.