“Civilian control of the military is a basic principle of the American Constitution”; so runs the commonplace. It is the thesis of this article that the cliché could hardly be more inaccurate, for actually the American Constitution in the twentieth century obstructs the achievement of civilian control. It is well known that civil supremacy was a major concern of the Framers. They provided for it in the only form in which they knew it. But civilian control in the eighteenth century is very different from civilian control in the twentieth century: the Constitution which was expertly designed to provide for it then, for this very reason, frustrates it now. In presenting this thesis, it is necessary: (1) to show how the meaning of civilian control has changed over the intervening years; (2) to describe the Framers' concept and show how it was embodied in the Constitution; and (3) to demonstrate how the provisions which they thought would guarantee it impair its effectiveness today.