Command over the U.S. Armed Forces is established in the Constitution. The sole power of command is vested in the President by Article II as Commander-in-Chief. The Constitution presumes the existence of "executive Departments" headed by "principal officers", whose appointment mechanism is provided for in the Appointments Clause. This allowance in the Constitution formed the basis for creation of the Department of Defense in 1947 by the National Security Act. The DoD is headed by the Secretary of Defense, who is a civilian and member of the Cabinet. The Defense Secretary is second in the U.S. Armed Forces chain of command, with the exception of the Coast Guard, which is under the Secretary of Homeland Security, and is just below the President and serves as the principal assistant to the President in all defense-related matters. Together, the President and the Secretary of Defense comprise the National Command Authority, which by law is the ultimate lawful source of military orders.
Military history is often considered to be the history of all conflicts, not just the history of the state militaries. It differs somewhat from the history of war, with military history focusing on the people and institutions of war-making, while the history of war focuses on the evolution of war itself in the face of changing technology, governments, and geography.
This continued in the 19th century, with publications like Punch in the British Empire and Le Père Duchesne in France, poking fun at the military establishment. This extended to media other print also. An enduring example is the Major-General's Song from the Gilbert and Sullivan light opera, The Pirates of Penzance, where a senior army officer is satirised for his enormous fund of irrelevant knowledge.
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.