Question

The secret agreement in which germany promised to return territory from the united states to mexico in exchange for mexico's assistance during world war i was the

Answer 1

This was the Zimmerman Telegram!!!

It was sent out January 1917, before the US entered the war.

It was said to be intercepted by the British forces, and after it leaked, Zimmerman confessed March 3rd.

Zimmerman's confession made Americans really hostile, thus helping progress the Anti-German sentiment and pro-war agenda for the US.