cause of effect:The Zimmerman telegram
Cause: The Zimmerman telegram was sent by Arthur Zimmermann, the German foreign minister, to the German ambassador in Mexico City on January 16, 1917.
Effect: The Zimmerman telegram was intercepted and deciphered by British intelligence and then shared with the United States. The telegram proposed a military alliance between Germany and Mexico, with the aim of encouraging Mexico to declare war on the United States if the U.S. entered World War I. This revelation played a significant role in convincing the United States to join the war against Germany, as it outraged American public opinion and intensified anti-German sentiment. Consequently, on April 6, 1917, the United States declared war on Germany and entered World War I.