In every state, the command of the armed forces is the ultimate component of executive power. Article II of the Constitution, adapting British practice, designates the President commander-in-chief both of the nation's armed forces and of the state militia when it is called into national service. Article IV, guaranteeing each state a republican form of government, somewhat qualifies that authority. It provides that the national force be used to suppress domestic violence only on application of the state legislature or of the governor when the state legislature cannot be convened.
With regard to domestic (and republican) tranquillity, it became apparent soon after 1789 that the deference of Article IV to states ' rights did not permit the national government fully to protect the peace of the United States. Although state governments dealt with most episodes of domestic disorder—and still do—some of those episodes had a national dimension. As early as 1792, Congress declared that "it shall be lawful for the President" to use national troops or call forth the militia whenever he deems such action necessary to protect the functioning of the government or the enforcement of its laws. President george washington leading more than 12,000 national guardsmen to suppress the whiskey rebellion of 1793 is the classic symbol of an independent national power to enforce what the President, echoing Jean-Jacques Rousseau, called "the general will." This power has been invoked regularly, most notably during and after the civil war, but also in major strikes affecting the national economy (in re debs, 1895) and in the enforcement of judicial decisions ordering racial desegregation during the 1950s and 1960s. President william howard taft used the national force to protect Asian aliens threatened by a local mob, relying on his duty as President to carry out the international responsibility of the United States for the safety of aliens.
The formula of the 1792 statute, like that used in later statutes, straddles an unresolved controversy between the President and Congress. Congress insists that its power to pass laws necessary and proper to implement the President's authority as commander-in-chief includes the right to restrict the President's capacity to act. All Presidents, on the other hand, while recognizing the necessity for legislation in many situations, claim that statutes cannot subtract from their constitutional duty and power to preserve the Constitution and enforce the laws. Although the pattern of usage is by no means uniform, Presidents generally conform to statutes that purport to reinforce and structure the President's use of the armed forces in domestic disorders, at least as a matter of courtesy, unless "sudden and unexpected civil disturbances, disasters, or calamities," in the language of Army regulations, leave no alternative. Some Presidents have even paid lip service to the posse comitatus act (1878), a dubious relic of the end of Reconstruction. That act prohibits the use of the Army in suppressing domestic turbulence unless "expressly" authorized. Presidents have evaded this restriction by employing marines for the purpose.
Modern statutes usually retain the ancient requirement of a public proclamation before force is used to restore order, although Presidents sometimes ignore the tradition. The use of force by the President (or by a governor) in dealing with civil disorder does not alone justify suspending the writ of habeas corpus. According to the doctrine of ex parte milligan (1867) and other cases, the writ cannot be suspended so long as the courts remain capable of carrying out their duties normally.
The use of force as an instrument of diplomacy, or of war and other extended hostilities, does not involve issues of dual sovereignty but has presented significant constitutional conflicts both between Congress and the President, and between individuals and the state. (See war, foreign affairs, and the constitution.) The President's power as commander-in-chief under such circumstances goes far beyond the conduct of military operations. As the Supreme Court declared in Little v. Barreme (1804), it is also the President's prerogative to deploy troops and weapons at home and abroad in times of peace and war, and to use them when no valid law forbids him to do so. The purposes for which the President may use the armed forces in carrying on the intercourse of the United States with foreign nations are infinite and unpredictable. They include diplomatic ceremony and demonstrations of power; the employment of force in self-defense in order to deter, anticipate, or defeat armed attack against the interests of the United States, or any other act in violation of international law that would justify the use of force in time of peace; and the prosecution of hostilities after a congressional declaration of war. In actual hostilities, it is the President's sole responsibility to negotiate truces, armistices, and cease-fires; to direct the negotiation of peace treaties or other international arrangements terminating a condition of war; and to govern foreign territory occupied in the course of hostilities until peace is restored.
These powers are extensive. The use, threat, or hint of force is a frequent element of diplomacy. Military occupations lasted for years during and after the Civil War, the Philippine campaign, a number of Caribbean episodes, world war i, and world war ii. The Cold War has required the apparently permanent deployment abroad of American armed forces on a large scale; novel legal arrangements have developed to organize these activities. Although the broad political and prudential discretion of both the President and Congress is taken fully into account by the courts in reviewing such exercises of the commander-in-chief's authority, constitutional limits have nonetheless emerged.
In recent years Congress has effectively employed its appropriation power to qualify the President's discretion as commander-in-chief in conducting military or intelligence operations that are not "public and notorious" general wars under international law. While such contests between the power of the purse and the power of the sword are largely political, they raise the principle of the separation of powers applied in immigration and naturalization service v. chadha (1983). The judicial response to these contests can be expected further to clarify a particularly murky part of the boundary between the President and Congress.
Eugene V. Rostow
Bishop, Joseph W., Jr. 1974 Justice under Fire. New York: Charter House.
Corwin, Edward S. (1940) 1957 The President: Office and Powers 1787–1957. New York: New York University Press.
Wilcox, Francis 1971 Congress, the Executive, and Foreign Policy. New York: Harper & Row.