Which development helped push the United States toward involvement in World War I?

• A. Zimmermann Telegram
• B. Use of submarine warfare in the Atlantic
• C. Sinking of the Lusitania
• D. Assassination of Archduke Franz Ferdinand

Answer: (B)

Unrestricted submarine warfare in the Atlantic directly endangered the United States and its interests, making neutrality increasingly untenable. Germany’s policy to sink ships bound for Britain meant American vessels and citizens could be attacked on the high seas, threatening lives, trade, and the rights of neutrals. This created a clear, immediate security concern for the United States and pushed leaders to move toward involvement, especially as incidents like the sinking of passenger ships stirred public opinion and the war threat grew when Germany resumed such attacks in 1917. The Zimmermann Telegram added fuel to the fire by signaling a German plan against the United States, but the ongoing submarine threat itself was the pivotal factor that shifted the country from neutrality to active involvement.