What was the immediate cause of the US. entry into World War I?

1 Answer
Mar 27, 2017

The Zimmerman Telegram


In January 1917 British Intelligence intercepted and decoded a telegram from The German Foreign Office proposing a military alliance between Mexico and Germany if the US entered the 1st World War on the Allied side.
The British gave the telegram to the Americans and its authenticity was confirmed by the German Foreign Secretary, Arthur Zimmerman in March. The American public was aroused. The US declared War in April 9, 1917.