The United States entered World War I primarily due to Germany's resumption of unrestricted submarine warfare, which threatened American lives and commerce, and the interception of the Zimmermann Telegram in which Germany proposed a military alliance with Mexico against the US. These actions pushed the US, which had initially aimed to remain neutral, to declare war on Germany on April 6, 1917, to "make the world safe for democracy" as President Woodrow Wilson articulated.
Key Reasons for US Entry into WWI
- Germany's unrestricted submarine warfare resumed in 1917, targeting Allied and neutral ships, leading to the sinking of American merchant ships and loss of American lives.
- The Zimmermann Telegram revealed Germany's proposal to Mexico to join forces against the US, promising the return of lost territories.
- American economic interests were aligned with the Allies through loans and trade, creating a financial stake in their victory.
- Wilson framed the war as a moral crusade to protect democracy and prevent German domination of the world, appealing to idealism and national security.
- Prior incidents like the sinking of the Lusitania in 1915, which killed American passengers, swayed public opinion against Germany over time.
Political and Public Context
- Initially, most Americans and President Wilson favored neutrality due to the conflict being seen as a European war.
- Ethnic divisions existed in America, with German Americans and Scandinavian Americans favoring neutrality, and others sympathizing with Allied nations.
- By 1917, with the war dragging on and threats increasing, Wilson sought congressional approval to enter the war, which was granted overwhelmingly.
- The US then mobilized troops and resources to support the Allies, significantly impacting the course and outcome of the war.
In summary, the US entry into World War I was driven by a combination of direct threats to its security and commerce, diplomatic provocations, economic ties, and ideological motives framed by Wilson's vision for a democratic world order.
