7.11 Interwar Foreign Policy

Isolationism is the idea that the U.S. should avoid alliances and foreign wars. After the Senate rejected the League of Nations, the U.S. stayed out of binding alliances, but it remained deeply involved in world trade and diplomacy, so historians often describe the 1920s as 'independent internationalism'.

At the Washington Naval Conference (1921–1922), the U.S., Britain, Japan, France and Italy agreed to limit battleship building, with the U.S., Britain and Japan at a 5:5:3 ratio. The Dawes Plan (1924) arranged American loans to help Germany pay reparations to Britain and France, which then paid war debts back to the U.S. The Kellogg–Briand Pact (1928) had dozens of nations renounce war as a tool of national policy, but it had no enforcement.

When Japan seized Manchuria in 1931, the U.S. responded only with the Stimson Doctrine, refusing to recognize territory taken by force.

After decades of U.S. interventions in the Caribbean and Central America, Franklin Roosevelt announced a Good Neighbor Policy in 1933, promising not to intervene in Latin American countries' internal affairs. U.S. Marines left Haiti in 1934, the Platt Amendment was ended the same year, and when Mexico took over foreign-owned oil companies in 1938, the U.S. negotiated rather than sending troops. The policy improved relations and trade, though the U.S. still backed friendly dictators in some countries.

The Depression turned attention inward, and many Americans believed entering World War I had been a mistake. The Senate's Nye Committee (1934–1936) suggested that bankers and arms makers, 'merchants of death', had pulled the country into that war.

Congress passed Neutrality Acts in 1935, 1936 and 1937, banning arms sales and loans to nations at war and limiting Americans' travel on warring nations' ships. In other words, it tried to avoid the conditions that drew the U.S. into World War I. The 1937 act added cash-and-carry for nonmilitary goods: warring nations had to pay cash and carry the goods in their own ships.

Meanwhile aggression grew: Japan invaded China in 1937, and Germany under Adolf Hitler took Austria and Czechoslovakia in 1938–1939. The U.S. also took in few Jewish refugees fleeing Nazi persecution, turning away the ship St. Louis in 1939.

• After Germany invaded Poland in September 1939, Congress allowed cash-and-carry arms sales, which helped Britain and France, who controlled the seas.
• After France fell in 1940, FDR traded 50 old destroyers to Britain for bases (September 1940), and Congress passed the first peacetime draft.
• The America First Committee, with aviator Charles Lindbergh as its best-known speaker, argued the U.S. should stay out.
• FDR called the U.S. the 'arsenal of democracy' (December 1940) and described Four Freedoms worth defending (January 1941).
• Lend-Lease (March 1941) let the U.S. lend or lease weapons to Britain, and later the Soviet Union and others, without cash payment.
• In the Atlantic Charter (August 1941), FDR and Winston Churchill set out shared war aims (7.14). U.S. warships began escorting convoys and clashed with German U-boats.
• After Japan occupied southern French Indochina in July 1941, the U.S. froze Japanese assets and cut off oil exports, leading Japan to plan the attack on Pearl Harbor.