It is a conflict as old as mankind: humanities desire for peace versus a recognition of what also appears to be a part of man's make-up - an urge and a genius for making war on his fellow man. Democratic nations feel this conflict most keenly as recognizing the rights of the individual is the cornerstone principle of their governments. Autocratic and authoritarian governments will usually put the perceived needs of the state before the needs of individuals.
A reluctance to create a permanent standing Army and Navy was very much a part of the make-up of this country's Founding Generation. They felt that creating such a force would be a threat to their newly won freedoms. But being pragmatists, the Constitution that they created does layout the framework for our national defense. The American President is the Commander-in-Chief of our armed forces, giving a civilian the ultimate authority. Congress is granted the powers of the purse and the power to declare wars.
A slim majority of U.S. Presidents have served in the military, either on active duty or with the militia or National Guard. A surprising number of them held very high rank in the military. Beginning with our first President, General George Washington, Commander of the Continental Army, three U.S. Presidents held the rank of General of the Armies. The other two were U.S. Grant in the Civil War and Dwight Eisenhower in World War Two.
Andrew Jackson the "Hero of New Orleans" and William Henry Harrison both reached the rank of General in the War of 1812. Zachary Taylor fought in the War of 1812 and served as a Brigadier General in the Mexican-American War. Franklin Pierce, Rutherford B. Hayes and James Garfield all held the rank of General in the U.S. Army in the Civil War.
Several other U.S Presidents were also decorated soldiers and war heroes. William Mckinley was wounded in the Civil War. Theodore Roosevelt served as a Colonel with the Rough Riders in the Spanish-American War and was recommended for the Medal of Honor. Harry Truman was a artillery Captain in the First World War. John F. Kennedy was captain of a P.T. Boat and George H. W. Bush was a navy pilot, both in World War II.
At many points in our history having served in the military was a prerequisite for seeking political office. This was especially true after the two major all-inclusive wars of U.S. history - the Civil War and World War Two. Beginning with Harry Truman becoming President in 1945, every U.S. President, except William Clinton, has worn the uniform of the U.S. military. With the ending of conscription (the Draft) in 1973, that run of veterans (1945-1993) in the White House will most likely never be matched again.