Why did the United States enter World War I?

Answers from the USCIS list

Give one of these answers. Words in light (parentheses) are optional.

• Because Germany attacked U.S. optional: (civilian) ships
• To support the Allied Powers optional: (England, France, Italy, and Russia)
• To oppose the Central Powers optional: (Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria)

Our explanation

World War I began in Europe in 1914. The U.S. joined in 1917, after Germany attacked U.S. ships. The U.S. fought with the Allied Powers (England, France, Italy, and Russia) against the Central Powers, including Germany.

Remember it

German attacks on U.S. ships. WWI Allies spell FIRE: France, Italy, Russia, England.

Source

USCIS 2025 Study Guide (M-1175) p. 63: “In 1914, a war started in Europe … the U.S. did not join the war until 1917.” M-1778 (09/25) Q101: “Because Germany attacked U.S. (civilian) ships” / “To support the Allied Powers”.

• 128 Civics Questions and Answers (2025 version), M-1778 (09/25) (PDF, USCIS)

Last checked on September 29, 2026.

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Easy to mix up with

• 106Why did the United States enter World War II?