Document Type


Publication Date



Since World War II, it has become increasingly common practice for presidents to use non-defensive military force abroad without obtaining congressional pre-approval, thereby leaving Congress with no meaningful role in the decision. This modern practice is clearly at odds with the Constitution’s text and original meaning. A wealth of scholarly commentary concludes that the Constitution grants Congress alone the power to authorize non-defensive military force. Although not expressly mentioned in the Constitution, ample commentary also concludes that a president has inherent constitutional power only to defend the nation from an actual or impending attack.

This Essay rejects the notion that a president’s independent constitutional authority to use non-defensive military force is, as a matter of constitutional law, left solely to the routine political give and take of the elected branches. In a republic based upon fundamental individual rights to life, liberty, and property—and of a limited central government constrained by fundamental law—legislative acts and well-accepted principles of necessity must govern a president’s legal authority to invade individual rights through the use of military force. A more complete contextual and structural reading of the Constitution’s text, as well as early government practice and relevant Supreme Court precedent, demonstrate that the Framers and ratifiers of the Constitution believed these basic, rule-of-law and separation-of-powers principles to be etched into the Constitution’s original design.

This Essay briefly reviews the current situation and comprehensively surveys the Constitution’s allocation of war- and military-related powers to demonstrate Congress's extensive authority over war and the nation's armed forces. This review strongly confirms the view that the Constitution requires Congress to affirmatively authorize all non-defensive military force and provides Congress with several powers to check a president's use and command of the military. It then briefly posits some of the reasons the relevant constitutional norms have eroded, clarifies why aberrant past practice cannot amend the Constitution's separation of war powers, and explains why Congress must reestablish its authority, briefly suggesting two ways that it may do so.