The New Deal era was the principal watershed in twentieth-century American constitutional development. The profound economic crisis that gripped the nation during the Great Depression inspired a period of extraordinary legislative ferment, generating a series of strikingly wide-ranging and far-reaching changes in the American legal and constitutional order. On the eve of World War II, Congress would wield an unprecedented degree of authority over the nation’s peacetime economy. The national legislature underwrote a voluminous array of spending programs to relieve distress and to stimulate economic growth, while at the same time it enacted a remarkable succession of regulatory programs designed to restore health to the economy. The administration of these new programs called for the creation of new federal agencies and the significant expansion of existing ones, resulting in an explosive growth in the size and power of the federal bureaucracy and the full flowering of the administrative state.

At the apex of this burgeoning fiscal and administrative apparatus stood the office of the presidency, supported by a significantly expanded staff and invested with enhanced authority over agencies within the executive branch. Just as the chief executive emerged from the Depression with greater authority over the administration of domestic affairs, so the commander-in-chief would enter World War II with greater discretion over the conduct of American foreign policy. Meanwhile, the federal judiciary receded from its traditional role as the umpire of the federal system and the guardian of vested rights, but would become increasingly assertive in the vindication of civil rights and civil liberties, such as freedom of speech and rights of the accused.