The “war powers” to which the President may lay claim by virtue of the Constitution rest on the provision in Article 2, Sec. 2, which provides that he “shall be Commander-in-Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States.” Since the War Clause –Article I, Sec. 8—vests in Congress the authority to “declare war,” it is necessary to examine the Commander-in-Chief Clause in concert with that provision. The Framers, after all, created a system of integrated parts and powers. To what degree, if any, are war powers shared? To what degree may the executive and legislative branches act independently in the exercise of American military power? More specifically, does the Commander in Chief Clause empower the president to unilaterally initiate war or lesser military hostilities? Answers to these, and related questions, may be derived from the debates in the Constitutional Convention, state ratifying conventions, the Federalist Papers and other contemporaneous writings, Supreme Court decisions rendered at the dawn of the Republic, and early presidential interpretations of the Constitution. These sources clearly established that Congress, alone, possesses the “war power”—the authority to declare war and authorize the use of military force on behalf of the American people. The president, as James Madison and other delegates explained, was vested with the power to “repel invasions.” Once war was authorized by Congress, or begun through invasion, the president, in his capacity as Commander in Chief, was expected to conduct the war, although he was subject to directions and instructions imposed by Congress. Let us explore the Framers’ blueprint for matters of war and peace, and how they envisioned the integration of the War Clause and the Commander in Chief Clause.
The Constitutional Convention severed the authority to decide for war from the power to conduct it. The Framers’ decision to withhold from the President the power to commence war signaled a dramatic departure from the existing models of government that placed the war power, indeed virtually all foreign affairs powers, in the hands of the executive. In The Second Treatise of Government (1690), John Locke had described three branches of government: legislative, executive and federative. According to Locke, the federative power, or what we today refer to as the power to conduct foreign affairs, encompassed “the power of war and peace, leagues and alliances, and all the transactions withal persons and communities without the commonwealth.” The power, moreover, was “almost always united” with the executive. The separation of the executive and federative powers, Locke warned, would bring “disorder and ruin.” Similarly, Sir William Blackstone, in his distinguished Commentaries on the Laws of England (1765-1769), had explained that the king enjoyed absolute power over foreign affairs and war: the authority to send and receive ambassadors, make treaties and alliances, make war or peace, issue letters of marque and reprisal, command the military, raise and regulate fleets and armies, and represent the nation in its intercourse with foreign governments.
Despite their familiarity with the English scheme of governance, the Framers, in what can only be described as a stunning move, granted Congress the greatest share of the nation’s foreign affairs powers. Congress was vested with the sole and exclusive authority to initiate war. The Constitution withheld from the President the sole power to make treaties, making him share that power with the Senate. James Madison and Alexander Hamilton referred to this combination as a “fourth branch” of government, which they expected would manage most of the country’s foreign policy responsibilities. The President was granted the authority to receive ambassadors, an act that entails important international legal obligations. But the founding trio of Madison, Hamilton and Jefferson did not view the reception or “recognition” clause as a font of discretionary executive power to decide whether the United States would have relations with other nations or to determine unilaterally the tone and temper of those relations. Rather, the Framers understood the recognition power as a narrow, clerk-like function or duty imposed as a matter of convenience on the President, rather than Congress, to carry out the nation’s obligation under international law to receive ambassadors from sovereign countries. The President was granted the authority to send ambassadors abroad but only after the Senate approved his nominations. He was not vested with the monarchical power to issue letters of marque and reprisal; that power was granted to Congress. Nor was he given the authority to raise and regulate fleets and armies. That power, too, was left with Congress. Finally, Congress was also granted plenary authority over foreign commerce.