World War II

The experiences of World War I and the Great Depression left the United States firmly isolationist. Congress passed a number of measures during the 1930s to ensure that the nation remained neutral in the impending European conflict. But events made neutrality impossible for the United States. When the Japanese bombed Pearl Harbor in 1941, the nation was once again plunged into global war.

Waging Total War

In United States v. Curtiss-Wright Export Corporation (1936), the Supreme Court held that the president has the constitutional authority to act as the voice of the nation in foreign affairs. The opinion supported expansive foreign relations powers for the president, and Roosevelt used these powers to the hilt as World War II unfolded. After Congress declared war on Japan and Germany in 1941, the Court upheld domestic wartime controls passed by Congress as constitutional exercises of the war powers.

Internment of Japanese-Americans

The compulsory relocation of more than 100,000 Japanese Americans remains one of the most troubling aspects of twentieth-century constitutional history. Under Executive Order No. 9066, Americans of Japanese descent were rounded up and relocated to detention camps without hearing or charge as a preventive security measure. A series of cases challenged various aspects of the internment program. The Court unanimously upheld a curfew order in Hirabayashi v. United States (1943) but was bitterly divided on the constitutionality of the relocation order and on the detention of Japanese Americans in Korematsu (1944) and Endo (1944) cases.

Military Trial of Civilians

Immediately after the Pearl Harbor attack, the Governor of Hawaii suspended the writ of habeas corpus and imposed martial law pursuant to the Hawaiian Organic Act of 1900. For the first time since the Civil War, U.S. civilians came under military jurisdiction. In Duncan v. Kahanamoku (1946) the Court avoided the underlying constitutional issue of whether Congress could subject civilians to military justice outside a war zone and decided the case on narrow statutory grounds instead.

Jurisdiction over Enemy Military Personnel

In Ex parte Quirin (1942) the Supreme Court ruled on whether enemy saboteurs captured in the United States could be tried by military commissions when the civil courts were open and available. The Court unanimously held that the president as commander in chief has authority to establish military commissions for the purpose of trying enemy saboteurs. It further held that enemy military personnel are not protected by the United States Constitution.

War Crimes Trials

After the surrender of Japan, the United States established military tribunals for the trial of alleged war criminals. The controversial trial and conviction of General Tomoyuki Yamashita for war crimes in the Philippines raised serious questions about the procedures and rules of evidence employed by the commission that tried him. The Court upheld the jurisdiction of the military to try Yamashita but declined to rule on the fairness of his trial on the ground that the proceedings of military commissions are not subject to judicial review. The Court also held that the war powers of the government do not automatically cease with the cessation of hostilities.

War Powers in Peacetime

The Yamashita ruling on the persistence of the war powers after the end of hostilities was cited by the Court in Woods v. Miller (1948) to uphold a 1947 act of Congress continuing wartime rent controls.

Wartime Treason

World War II required the Court to revisit the treason standard enunciated by Chief Justice Marshall in the 1807 treason trial of Aaron Burr. Marshall held that a defendant must be proved to have committed an overt act against the United States in order to be found guilty of the crime of treason. In Cramer v. United States (1945) and Haupt v. United States (1947) the Court held that the overt act alleged must be underpinned by treasonous intent.