While the risk of soldiers quartered in homes—one of the Framers’ chief complaints—is the least of our worries today, it was hardly the Framers’ only concern. They also feared the inspiring “man on horseback”—the charismatic military hero who could use his outsize popularity to thwart the initiatives of politically elected civilians. (Think of General Colin Powell’s highly effective campaign against President Bill Clinton’s efforts in the 1990s to lift the ban on gays in the military.) And they worried about the opposite problem, too—the danger posed by the potential rise of corrupt political leaders, who might seek to keep the military in line by insisting that it internalize the values not of professional ethics or the rule of law, but of the particular civilian leader in charge. As the political scientist Samuel Huntington famously explained in The Soldier and the State, such a mechanism could tie the military closely to one political party, and thereby make the military an enemy of democratic governance once that party left power.

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In the end it was the experience of General George Washington that led the Framers to accept the necessity of a professional military. Washington’s struggles to manage bands of untrained rebel fighters made him a powerful advocate for the indispensability of training, regular structure, and rules of discipline for ensuring military effectiveness. The constitutional question was how, then, to capture the benefits of such a military while mitigating its many risks. The Constitution’s answer: Divide control over the military between the president and Congress. The president would command the armed forces; Congress would regulate them.

And regulate the military Congress has, with many of the Framers’ concerns in mind. To help insulate the military from partisan politics, for example, the law prohibits active-duty personnel from participating in partisan fundraising or rallies, from using their official authority or influence to advocate in an election, and from soliciting votes for any candidate. Elaborate rules of discipline and good conduct (including prohibitions against war crimes) are also codified in statutes passed by Congress; administered in key respects by military lawyers who report through their own, independent chain of command inside the Pentagon; and backed by federal law prohibiting any commanding officer from attempting to unduly influence the operation of this system of military justice. Historically, Congress even enacted legislation enabling a court-martial to reverse the president’s dismissal of an officer if the court determined the dismissal was “wrongful.” (This particular law, passed during the Civil War, was one neither President Lincoln nor his attorney general found objectionable.) In the years after September 11, professional military lawyers leveraged this legal framework against civilian political efforts to lift limits on torture and cruelty toward detainees.