When war broke out in Europe in the summer of 1914, between the Allies (Britain, France, Russia) and the Central Powers (Germany, Austria-Hungary, the Ottoman Empire), most Americans wanted no part of it. The country had just flexed its power in its own hemisphere, but Europe's war seemed far away.
Key idea
The U.S. stayed neutral from 1914. German submarine attacks (the Lusitania, 1915; unrestricted submarine warfare, from February 1917) and the Zimmermann Telegram (made public March 1917) led Congress to declare war on Germany on April 6, 1917.
Why it works
Neutral did not mean untouched. Britain blockaded Germany, so American trade and loans flowed mostly to the Allies. Germany answered with submarines (U-boats), which sank ships without warning. After the Lusitania went down in May 1915, killing 1,198 people including 128 Americans, Wilson protested, and in 1916 Germany promised to limit its attacks. In January 1917 Germany decided to sink all ships near Britain anyway, gambling it could win before American troops arrived. Then the British decoded a telegram from Germany's foreign secretary, Arthur Zimmermann, offering Mexico an alliance.
On April 2, 1917, Wilson asked Congress for war, saying the world must be made "safe for democracy." The Senate voted 82 to 6 and the House 373 to 50; Jeannette Rankin, the first woman in Congress, voted no.
Work it through
Worked example: Long-term and immediate causes
Sort these: American trade with the Allies; the Lusitania; unrestricted submarine warfare in 1917; the Zimmermann Telegram.
- Long-term: trade and loans tied the U.S. economy to the Allies (1914 to 1917).
- Background: the Lusitania (1915) turned opinion against Germany but did not bring war.
- Immediate: unrestricted submarine warfare and the Zimmermann Telegram (early 1917).
Answer: Trade and the Lusitania were background; the 1917 U-boat campaign and the telegram were the immediate causes.
Common mistake
Many students think the Lusitania sinking brought the U.S. into the war right away. It came almost two years before the U.S. entered. The renewed submarine campaign and the Zimmermann Telegram in early 1917 were the immediate causes.