Analyze the causes of World War I, US neutrality, and the reasons the United States entered the war in 1917, including unrestricted submarine warfare and the Zimmermann Telegram (TEKS US History RC1 History; RC4 Science, Technology, and Society).

What this topic is asking

The United States stayed out of World War I for nearly three years, then entered in 1917. The TEKS want you to explain the causes of the war, why the United States was at first neutral, and the specific events (especially submarine warfare and the Zimmermann Telegram) that finally pushed it in. This is a Reporting Category 1 (History) topic with a science and technology angle (the submarine).

The causes of the war in Europe

American neutrality

When war broke out in 1914, the United States declared neutrality, in keeping with its long-standing policy of staying out of European conflicts. Most Americans wanted no part of the war. The country traded with both sides, although in practice it sold far more goods and loans to the Allies (Britain and France) than to the Central Powers. Neutrality, however, became harder to maintain as the war at sea intensified.

Submarine warfare and the Lusitania

In 1915 a German U-boat sank the British passenger liner Lusitania, killing nearly 1,200 people, including over 100 Americans. Outrage was intense. Germany briefly backed off, but when it resumed unrestricted submarine warfare in early 1917, sinking American ships, neutrality became untenable.

The Zimmermann Telegram

The final straw was the Zimmermann Telegram, a secret German message (intercepted by the British and made public) proposing a military alliance with Mexico against the United States. Germany promised that if Mexico joined and Germany won, Mexico would regain territory it had lost to the United States, including Texas. To Americans, the telegram proved that Germany was a direct threat to their own country, not just to Europe.

The decision to enter

In April 1917, President Woodrow Wilson asked Congress to declare war on Germany, framing it as a crusade to make the world "safe for democracy." Congress agreed. American troops (the American Expeditionary Force) and vast resources then tipped the balance toward an Allied victory in 1918.

Try this

Q1. State the four long-term causes of World War I. [2]

• Cue. Militarism, alliances, imperialism, and nationalism (M-A-I-N).

Q2. Explain how submarine warfare and the Zimmermann Telegram pushed the United States into the war. [2]

• Cue. Unrestricted submarine warfare sank ships (including the Lusitania and later American vessels), killing Americans and violating neutral rights; the Zimmermann Telegram revealed Germany seeking an alliance with Mexico against the United States, convincing Americans that Germany directly threatened them, so Wilson asked Congress to declare war in 1917.