Not appearing in the Constitution, the phrase "war powers" nonetheless describes a cluster of powers exercised by the President or Congress, together or separately, to combat both domestic insurgency and foreign military enemies. They comprise those activities necessary "to wage war successfully," including the raising of troops, the provision of equipment and supplies, the mobilization of opinion, and the maintenance of security in loyal areas (during civil war or insurgency) or on the home front (during foreign war).
As with all governmental activity, the legitimacy of the war powers depends ultimately on explicit or implicit sources in the Constitution. Among these are the grants to Congress of authority "to declare War," to raise, maintain, and make rules for federal military forces, and "to provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions." Other sources include the Article I authorization to suspend the privilege of the writ of HABEAS CORPUS "when in Cases of Rebellion or Invasion the public Safety may require it," the Article II clauses making the President COMMANDER-IN-CHIEF, giving him power to make treaties subject to Senate consent, and charging him to "take Care that the Laws be faithfully executed," and the Article IV commitments guaranteeing "to every State ? a REPUBLICAN FORM OF GOVERNMENT " and pledging protection against invasion and domestic violence. Magnifying all these grants is the NECESSARY AND PROPER CLAUSE.
Contrariwise, only in exceptional circumstances have officials instituted TREASON prosecutions, for in Article III the Framers laid out strict evidentiary requirements, owing to the crime's draconian connotations. But such seemingly plausible restrictions as the FIRST AMENDMENT and Fifth Amendment, the principle of SEPARATION OF POWERS, and the rule against delegation of power have seldom proved real barriers to effective wartime government; and generally JUDICIAL REVIEW has had little impact on the power to make war.
As early as 1792, Congress empowered the President to call forth state militias when "combinations too powerful to be suppressed by the ordinary course of judicial proceedings" prevented the execution of federal law. Used during the WHISKEY REBELLION (1794), and subsequently modified to include regular military forces and to clarify the President's authority to determine the existence of emergency, this provision later helped undergird President ABRAHAM LINCOLN'S response to the siege of Fort Sumter. The ALIEN AND SEDITION ACTS of 1798 provide another early illustration of legislative-executive collaboration; adopted during the Quasi-War with France, they posed the enduring issue of reconciling CIVIL LIBERTIES with the perceived requirements of internal security.
Although Presidents THOMAS JEFFERSON and ANDREW JACKSON confronted serious opposition to enforcement of federal law during the Embargo and NULLIFICATION crises, the CIVIL WAR produced the first comprehensive test of the war powers' true potential. With only a slender statutory base?or none at all?for much of his action, Lincoln called out the militia, requested federal volunteer troops, increased the size of the regular army and navy, spent money from the treasury, established a naval blockade of the Confederacy, and suspended the privilege of the writ of habeas corpus. When Congress finally met at Lincoln's call, on July 4, 1861, it confronted not only a program already in place but...