Final answer:
The US entered WW1 primarily due to the Zimmermann Telegram, unrestricted submarine warfare by Germany, and economic interests tied to the Allies, as well as underlying nationalism and complex alliances.
Step-by-step explanation:
Causes for US Involvement in WW1:
The United States entered World War I due to a variety of factors that tipped the balance towards American intervention. Among these causes were:
- Zimmermann Telegram: A secret communication from the German foreign minister to Mexico proposing a military alliance against the United States, promising the return of territories lost during the Mexican-American War.
- Submarine Warfare: Germany’s unrestricted submarine warfare, which led to the sinking of civilian and neutral ships, including those with Americans aboard, was a direct challenge to US neutrality and sovereignty.
- Economic Interests: The American economy was closely tied to the Allies, and German attacks on shipping threatened these economic relations.
These factors, combined with underlying issues of nationalism and a complex web of alliances among European powers, ultimately led President Woodrow Wilson to bring the United States into the conflict on the side of the Allies, despite initial reluctance.