Article I, Section 8, Clause 11:
[The Congress shall have Power . . .] To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water; . . .
The Constitution of the United States is a law for rulers and people, equally in war and in peace, and covers with the shield of its protection all classes of men, at all times, and under all circumstances. No doctrine, involving more pernicious consequences, was ever invented by the wit of man than that any of its provisions can be suspended during any of the great exigencies of government. Such a doctrine leads directly to anarchy or despotism, but the theory of necessity on which it is based is false; for the government, within the Constitution, has all the powers granted to it, which are necessary to preserve its existence; as has been happily proved by the result of the great effort to throw off its just authority.  1
Ex parte Milligan, from which these words are quoted, is justly deemed one of the great cases undergirding civil liberty in this country in times of war or other great crisis. The Court held that, except in areas in which armed hostilities have made enforcement of civil law impossible, constitutional rights may not be suspended and civilians subjected to the vagaries of military justice. Yet, the words were uttered after the cessation of hostilities, and the Justices themselves recognized that with the end of the shooting there arose the greater likelihood that constitutional rights could be and would be observed and that the Court would require the observance. 2 This pattern recurs with each critical period.
That the power of Congress to punish seditious utterances in wartime is limited by the First Amendment was assumed by the Court in a series of cases, 3 in which it nonetheless affirmed conviction for violations of the Espionage Act of 1917. 4 The Court also upheld a state law making it an offense for persons to advocate that citizens of the state should refuse to assist in prosecuting war against enemies of the United States. 5 Justice Holmes matter-of-factly stated the essence of the pattern that we have mentioned:
When a nation is at war many things that might be said in time of peace are such a hindrance to its effort that their utterance will not be endured so long as men fight and that no Court could regard them as protected by any constitutional right. 6
By far, the most dramatic restraint of personal liberty imposed during World War II was the detention and relocation of the Japanese residents of the Western states, including those who were native-born citizens of the United States. When various phases of this program were challenged, the Court held that, in order to prevent espionage and sabotage, the authorities could restrict the movement of these persons by a curfew order 7 and even exclude them from defined areas by regulation, 8 but that a citizen of Japanese ancestry whose loyalty was conceded could not continue to be detained in a relocation camp. 9
A mixed pattern emerges from an examination of the Cold War period. Legislation designed to regulate and punish the organizational activities of the Communist Party and its adherents was at first upheld, 10 and then in a series of cases was practically vitiated. 11 Against a contention that Congress’s war powers had been used to achieve the result, the Court struck down for the second time in history a congressional statute as an infringement of the First Amendment. 12 It voided a law making it illegal for any member of a
communist-action organization to work in a defense facility. 13 The majority reasoned that the law overbroadly required a person to choose between his First Amendment-protected right of association and his right to hold a job, without attempting to distinguish between those persons who constituted a threat and those who did not. 14
On the other hand, in New York Times Co. v. United States, 15 a majority of the Court agreed that in appropriate circumstances the First Amendment would not preclude a prior restraint of publication of information that might result in a sufficient degree of harm to the national interest, although a different majority concurred in denying the government's request for an injunction in that case. 16