The British gave President Wilson the Zimmerman telegram on February 24, and on March 1 the U.S. press reported on its existence. The American public was outraged by the news of the Zimmerman telegram and it, along with Germany's resumption of submarine attacks, helped lead to the U.S. to join the war
The reason they adopted this was to "A.Justify Revolution". This was because up to this moment there really had not been a formal explanation of the goals of the movement.
