—The use of mercenaries during the American Revolution should inform the debate over the regulation of private military firms (PMFs) today. This Comment examines the historical use of mercenaries to demonstrate that a standing army, in the experience and understanding of the Framers, included both enlisted citizens and private enterprises who performed a wide range of essential military functions. It further argues that PMFs as they currently function in Iraq and Afghanistan fall squarely within the Framers’ broad conception of a standing army. The debates about national defense following the American Revolution show that the Framers accepted a standing army in the new nation solely on the condition that it be regulated and controlled by Congress. However, PMFs are currently governed as civilians by the terms of their contracts with the Executive Branch. This arrangement has led to a number of serious problems, including widespread waste and fraud resulting from deficient oversight, lack of accountability for brutal human rights violations, and distortion of the democratic decisionmaking process. This Comment argues that treating PMFs as civilians for the purposes of regulation is misguided, both as a constitutional and practical matter. Congress must exert control over PMFs using the same system that governs the military, in accordance with the separation of powers over national defense established at the framing.