The Republican governments of the 1920s carried out active, probusiness policies while undermining much of the progressive legacy by neglect. The Washington Naval Conference indicated Americas desire to withdraw from international involvements. Sky-high tariffs protected Americas booming industry but caused severe economic troubles elsewhere in the world.

As the Harding scandals broke, the puritanical Calvin Coolidge replaced his morally easygoing predecessor. Feuding Democrats and La Follette progressives fell easy victims to Republican prosperity.

American demands for strict repayment of war debts created international economic difficulties. The Dawes plan provided temporary relief, but the Hawley-Smoot Tariff proved devastating to international trade.

The stock-market crash of 1929 brought a sudden end to prosperity and plunged America into a horrible depression. Herbert Hoovers reputation collapsed as he failed to relieve national suffering, although he did make unprecedented but limited efforts to revive the economy through federal assistance.