AMSCO 7.11 Inerwar Foreign Policy

Overview

AMSCO Topic 7.11, Interwar Foreign Policy, covers how the United States tried to stay out of another world war between 1919 and 1941, and why that effort ultimately failed. The big idea: America wasn't purely isolationist after World War I. It refused to join the League of Nations, but it still signed treaties, invested heavily overseas, and intervened militarily when it wanted to. AMSCO calls this unilateralism, acting alone on America's own terms. The chapter runs from the disarmament conferences of the 1920s through the rise of fascism, the Neutrality Acts, and FDR's step-by-step moves toward aiding Britain after 1939. This is the bridge between Period 7's domestic story (Depression, New Deal) and U.S. entry into World War II.

Peace Efforts of the 1920s

Republican presidents wanted peace on the cheap. Disarmament treaties let them cut defense spending while looking like global peacemakers.

Washington Conference (1921)

Secretary of State Charles Evans Hughes hosted nine nations in Washington, D.C. to talk naval disarmament and Pacific tensions. It was the biggest achievement of Harding's presidency, producing three treaties:

• Five-Power Treaty set a battleship ratio: U.S. 5, Britain 5, Japan 3, France 1.67, Italy 1.67. The U.S. and Britain also agreed not to fortify their Pacific possessions; Japan faced no such limit.
• Four-Power Treaty had the U.S., France, Britain, and Japan agree to respect each other's Pacific territory.
• Nine-Power Treaty committed all nine nations to the Open Door policy and China's territorial integrity.

Kellogg-Briand Pact (1928)

American women led a peace movement to outlaw war itself (Jane Addams won the 1931 Nobel Peace Prize for her efforts). The result: Secretary of State Frank Kellogg and French Foreign Minister Aristide Briand arranged a pact, signed by nearly every nation, renouncing aggressive war. It was toothless for two reasons. It allowed "defensive" wars, and it had no enforcement mechanism against violators.

Business Diplomacy, Tariffs, and War Debts

The 1920s presidents used diplomacy to serve American business. Military intervention declined while economic influence exploded; U.S. investment in Latin America doubled between 1919 and 1929.

• Latin America: Coolidge's ambassador Dwight Morrow peacefully resolved a 1927 dispute over Mexico's claim to its oil and mineral resources. Troops stayed in Nicaragua and Haiti but left the Dominican Republic in 1924.
• Middle East: Hughes won oil-drilling rights for U.S. companies in a region Britain had dominated.
• Fordney-McCumber Tariff (1922) raised duties on foreign manufactured goods 25 percent. Short-term win for U.S. business, long-term disaster. Europe couldn't sell goods to repay war debts, retaliated with its own tariffs, and world trade weakened. AMSCO flags this as one cause of the Great Depression.

The Dawes Plan (1924)

The U.S. left WWI a creditor nation, owed over $10 billion by the Allies. Harding and Coolidge demanded full repayment, but Britain and France could only pay if they collected the $30 billion in reparations the Treaty of Versailles required from a bankrupt, inflation-wracked Germany. Banker Charles Dawes negotiated a money loop: U.S. banks lend to Germany, Germany pays reparations to Britain and France, and they repay war debts to the U.S. It worked until the 1929 stock market crash cut off the loans and the whole cycle collapsed. Only Finland ever repaid its debts in full, and the resentment on both sides pushed Americans further toward isolationism. Connect this to the global collapse covered in AMSCO 7.9 on the Great Depression.

Hoover and FDR's Diplomacy, 1929-1939

Both presidents pulled back from intervention in Latin America while the world grew more dangerous.

Hoover's Foreign Policy

• Took a goodwill tour of Latin America in 1929 before even taking office, then arranged for troops to leave Nicaragua by 1933 and Haiti by 1934.
• Manchuria, 1931: Japan invaded northeastern China, renamed it "Manchukuo," and set up a puppet government, defying the Open Door and the League of Nations. The League only passed a condemnation resolution; Japan walked out of the League for good. The crisis exposed the League as too weak to stop aggressors.
• Stimson Doctrine (1932): Secretary of State Henry Stimson declared the U.S. would refuse to recognize any regime established by force, citing the Nine-Power Treaty. The League endorsed it. Stronger than the League's response, but it deterred nothing.

FDR's Good-Neighbor Policy

Roosevelt's first inaugural in 1933 promised a "policy of the good neighbor" in the Western Hemisphere. Two motives: Depression-era businesses lacked money for dollar diplomacy anyway, and FDR wanted Latin American cooperation against rising militarism in Europe.

• At the 1933 Pan-American Conference in Montevideo, the U.S. pledged never again to intervene in Latin American internal affairs, repudiating Theodore Roosevelt's corollary to the Monroe Doctrine.
• At Buenos Aires in 1936, FDR personally pledged arbitration and hemispheric defense.
• Cuba: Congress nullified the Platt Amendment in 1934, keeping only the naval base at Guantanamo Bay.
• Mexico: When President Lazaro Cardenas seized U.S.-owned oil properties in 1938, FDR refused to intervene and told companies to negotiate.

Depression Diplomacy

Boosting the economy drove FDR's other moves. He recognized the Soviet Union in 1933 to open trade. The Tydings-McDuffie Act (1934) promised Philippine independence by 1946 to cut costs. And Secretary of State Cordell Hull's reciprocal trade agreements (1934) let the president cut tariffs up to 50 percent for nations that reciprocated, reversing the Fordney-McCumber approach.

Fascism Abroad, Isolationism at Home

The Depression plus post-WWI nationalist resentment produced dictatorships that would become the Axis powers (Germany, Italy, and Japan, allied by treaty in 1940).

• Italy: Benito Mussolini's Fascist Party marched on Rome in 1922 and installed him as "Il Duce." Fascism glorified nation and race through aggressive force.
• Germany: Adolf Hitler's Nazi Party exploited economic misery, resentment of the Treaty of Versailles, and anti-Semitism to gain control of the German legislature in early 1933.
• Japan: Militarists pushed for invading China and Southeast Asia to seize oil, tin, and iron for a "Greater East Asia Co-Prosperity Sphere." Full-scale war with China began July 7, 1937, including the Nanjing Massacre, in which Japanese troops killed around 300,000 Chinese residents.

Americans responded by digging in against war. Isolationism ran strongest in the Midwest and among Republicans.

• Nye Committee (1934): Senator Gerald Nye's investigation concluded the U.S. entered WWI to serve the greed of bankers and arms manufacturers, fueling the "WWI was a mistake" narrative. (Review what that war actually involved in AMSCO 7.5 on WWI military and diplomacy.)
• Neutrality Acts: The 1935 act banned arms shipments to belligerents and travel on their ships; the 1936 act banned loans and credits to belligerents; the 1937 act banned arms to either side in Spain's civil war.
• Spanish Civil War (1936-1939): Fascists under Francisco Franco fought republican Loyalists. FDR and most Americans sympathized with the Loyalists but the Neutrality Acts blocked aid. Franco won and set up a military dictatorship.
• America First Committee (1940): After WWII began, isolationists mobilized public opinion against FDR's pro-British policies, with Charles Lindbergh as a star speaker.

The Road to World War II

From 1935 to 1938, Britain and France responded to Fascist aggression with appeasement, letting Hitler take small bites in hopes of avoiding war. The U.S. went along. The pattern:

• Ethiopia, 1935: Mussolini invaded; the League and the U.S. objected but did nothing.
• Rhineland, 1936: Hitler remilitarized the region in open defiance of Versailles.
• China, 1937: Japan invaded; when Japanese planes sank the U.S. gunboat Panay, the U.S. quickly accepted Japan's apology.
• Sudetenland, 1938: At Munich, Britain's Neville Chamberlain and France's Edouard Daladier, with FDR's support, let Hitler take the German-speaking strip of Czechoslovakia. "Munich" became shorthand for appeasement.

FDR tested the waters with his 1937 quarantine speech, proposing democracies act together to isolate aggressors. Public reaction was so negative he dropped the idea. He did get Congress to raise military and naval budgets by nearly two-thirds in late 1938.

In March 1939, Hitler broke the Munich agreement and seized all of Czechoslovakia. Britain and France pledged to defend Poland. Then came the shock of August 1939: Stalin and Hitler signed a nonaggression pact, secretly agreeing to split Poland. On September 1, 1939, Germany's blitzkrieg (lightning war of air power and fast tanks) hit Poland, and Britain and France declared war. By June 1940, France had fallen in six weeks and Britain stood alone.

FDR Moves Toward Intervention

Once war began, Roosevelt chipped away at the neutrality laws because he believed British survival was crucial to U.S. security. Most Americans opposed Hitler but still wanted to stay out.

• "Cash and carry" (1939): A revised Neutrality Act let belligerents buy U.S. arms if they paid cash and used their own ships. Technically neutral; in practice it favored Britain, which controlled the seas.
• Selective Training and Service Act (1940): The first peacetime draft, registering men ages 21 to 35 and training 1.2 million troops in one year. Isolationists protested but were now outnumbered.
• Destroyers-for-bases deal (September 1940): With Britain under German bombing, FDR traded 50 older U.S. destroyers for rights to build bases on British islands in the Caribbean, dodging the outrage a direct sale would have caused.
• Election of 1940: FDR broke the two-term tradition by running for a third term against Republican Wendell Willkie.

The chapter's key terms point toward what comes next: FDR's "four freedoms" framing, the Lend-Lease Act (1941) that opened the aid spigot to Britain, the Atlantic Charter he signed with Churchill, and finally the Japanese attack on Pearl Harbor on December 7, 1941, which ended the isolationist debate and brought the U.S. into World War II.

Key Terms to Know

Practice and Next Steps

For the College Board's framing of this material, work through the 7.11 Interwar Foreign Policy course topic study guide, then browse the full set of APUSH AMSCO notes to keep moving through Period 7. This topic loves cause-and-effect and continuity-change questions, like how the Depression reshaped foreign policy or whether the 1920s were truly isolationist, so test yourself with APUSH multiple-choice practice and try writing about isolationism vs. interventionism with FRQ practice and instant scoring. For quick definition checks before a quiz, the APUSH key terms glossary has you covered.