World War I?

Question

What was the Zimmerman Note?

Answer 1

It was a letter from Germany to Mexico, in which the German government, represented by Mr. Zimmermann, tried to convince the Mexican governmet to declare war on the US.
When this was made public in America, many pro-German voices were silenced. The rest were ignored.

Answer 2

It was a diplomatic note originated by the Imperial German government to the government in Mexico, which promised German military support if Mexico invaded the U.S. to re-capture those lands which Mexico ceded to the U. S. in the Treaty of Guadalupe-Hidalgo which brought an end to the Mexican War in the 1840s. The Zimmerman note was the chief reason why President Wilson went to the Congress in April of 1917 and asked for a declaration of war against Imperial Germany.