Two days after terrorists attacked the World Trade Center and the Pentagon, a Harris poll conducted for Time/CNN reported that nearly two out of three Americans believed that the United States should "declare war." (1) A StrategyOne survey also conducted two days after the attacks found eighty-one percent of Americans in favor of such action, with only eight percent opposed. (2) That same day, nine members of Congress announced their support for a formal declaration of war. (3) The idea was quickly embraced in newspapers, (4) and even by Harvard Law School Professor Alan Dershowitz. (5)
In fact, as a constitutional matter, the President needed no approval from Congress to use lethal force in response to the terrorist attacks. Even the War Powers Resolution recognizes the independent constitutional power of the President to send U.S. forces into combat without legislative approval in response to an attack on the United States or its armed forces. (6) But as a political matter, getting Congress on record by statute in support of an effective response was very important.
Congress provided support for the President's response in the form of a joint resolution, providing in part:
[T]he President is authorized to use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons. (7) During the debate, concern was expressed about not giving the President a "blank check," (8) as Congress did in enacting the Gulf of Tonkin Resolution in August, 1964. (9) This argument undercut the cherished myth that Congress was not a full partner in committing the United States to war in Indochina and ignored the reality that "declarations of war" were by their nature "blank checks." To allay such concerns, language of the resolution seemed carefully designed to provide an "out" for legislators if the campaign went badly, as it would not be difficult to argue that any presidential action that later proved unpopular with voters was not "appropriate" and was thus unauthorized by Congress. In the end, however, even Senate Foreign Relations Committee Chairman Joseph Biden acknowledged that the resolution passed by Congress was "the constitutional equivalent of a declaration of war." (10)
As a matter of constitutional law, Senator Biden was exactly fight; a joint resolution authorizing the President to use military force fully satisfies any requirement for legislative approval under Article I, Section 8, Clause 11 of the Constitution. (11) But such statements betray a fundamental misconception of the relative roles of Congress and the President in the commitment and use of U.S. armed forces abroad and of the nature of war in the current international context. As a matter of international law, a formal declaration of war is an anachronistic irrelevancy. This misconception is the result of debates over the past three decades in which the historical understanding and development of war powers was neglected. Given the revived public interest in these issues, this is an opportune time to clarify the meaning of Congress's power to "declare war."
THE CONSTITUTIONAL ALLOCATION OF POWERS RELATED TO THE USE OF MILITARY FORCE
The debate over the constitutional separation of powers concerning the use of armed force abroad during the past three decades has been remarkably unimpressive. Few commentators have taken the time to look seriously at the historical aspect of the problem, and some act as if the 1972-73 War Powers Resolution debates were an issue of first impression.
Throughout most of our history, both Congress and the President understood that decisions regarding foreign affairs were different from domestic issues and were the province of the executive except in areas where the Constitution had made a clear exception. But by the early 1970s, the theoretical and textual basis of that distinction had apparently been forgotten at both ends of Pennsylvania Avenue. Legislators and their advocates looked through the Constitution and discovered there was no mention of "national security" or "foreign affairs." The theory quickly emerged that there should be no difference between domestic and foreign affairs and Congress was the "senior partner" in making policy for both. An examination of the original understanding, however, demonstrates the error of this current theory.
INSTITUTIONAL COMPETENCY AND THE EXECUTIVE POWER CLAUSE
Article II, Section 1 of the Constitution granted the new nation's "executive Power" to the President. (12) To the Framers, this was the primary grant of authority over the management of America's relations with the external world. As Professor Quincy Wright observed in his classic 1922 treatise, The Control of American Foreign Relations, "when the constitutional convention gave `executive power' to the President, the foreign relations power was the essential element in the grant, but they carefully protected this power from abuse by provisions for senatorial or congressional veto." (13)
Columbia Law Professor Louis Henkin noted in Foreign Affairs and the Constitution that the "executive power ... was not defined because it was well understood by the Framers raised on Locke, Montesquieu and Blackstone." (14) Each of these writers argued that the control of external intercourse was "executive" in its nature, and because of the relevant competencies of the institutions of government this power could not effectively be vested elsewhere. Locke explained in his Second Treatise on Civil Government:
These two Powers, executive and federative, though they be really distinct in themselves, yet one comprehending the execution of the Municipal Laws of the Society within itself upon all that are parts of it; the other the management of the security and interest of the public without, with all those that it may receive benefit or damage from, yet they are always almost united. And though this federative power in the well or ill management of it be of great moment to the commonwealth, yet it is much less capable to be directed by antecedent, standing positive laws, than [by] the Executive; and so must necessarily be left to the prudence and wisdom of those whose hands it is in to be managed for the public good. (15) In part from their study of theory, but also from their direct experience under the Articles of Confederation, (16) the Framers understood that Congress was institutionally incapable of effectively managing what Locke termed the business of "war, peace, leagues and alliances." Thus, these authorities were vested in the President, subject to several specific checks. Thomas Jefferson explained in April 1790:
The Constitution has divided the powers of government into three branches, Legislative, Executive and Judiciary, lodging each with a distinct magistracy.... [I]t has declared that the Executive powers shall be vested in the President, submitting special articles of it to a negative by the Senate.... The transaction of business with foreign nations is executive altogether. It belongs then to the head of that department, except as to such portions of it as are specially submitted to the senate. Exceptions are to be construed strictly. (17) Jefferson's view was embraced by President Washington, Supreme Court Chief Justice John Jay, and House Republican leader James Madison. (18) Indeed, it was but a reworded version of an argument Madison had made the previous year that was embraced by both Houses of Congress. (19)
THE POWER TO DECLARE WAR
Article I, Section 8, Clause 11, of the Constitution grants to Congress the power "[t]o declare War." (20) As Hamilton noted in 1793, this was an "exception" to the general grant of "executive power" to the President and thus was intended to be narrowly construed. (21)
One of the common errors in discussing the scope of this exception to the President's general "executive Power," a power reinforced by the specific recognition in Article II, Section 2, that "[t]he President shall be Commander in Chief of the Army and Navy of the United States," (22) has been to focus on the meaning of the term "War" under the Constitution. Congress is not granted the power of "War," but rather the more limited power "to declare War," which was a term of art from the Law of Nations with a clearly understood meaning in 1787.
The Framers were remarkably well-read men. The writers, such as Grotius, Vattel, Bynkershoek, and Burlamaqui, with whom they were familiar in this area, all argued that a formal declaration of war was unnecessary for defensive hostilities. In Book 3 of The Law of War and Peace, Grotius explained that "no declaration [of war] is required when one is repelling an invasion, or seeking to punish the actual author of some crime." (23) Even before Grotius, Alberico Gentili argued in 1612 that "when war is undertaken for the purpose of necessary defense, the declaration is not at all required." (24) Bynkershoek agreed that no formalities were necessary when responding to aggression, "since all laws permit the repelling of force by force." (25) Vattel wrote that "[h]e who is attacked and only wages defensive war, needs not to make any hostile declaration," (26) and Burlamaqui added that "this declaration takes place only in offensive wars." (27)
It was thus only when nations were at peace and one wished to initiate an offensive (or what we would today call an aggressive) war that it was necessary to declare war. This distinction between the President's right to use force defensively, but requiring legislative sanction to initiate a major offensive...