Mexico
Unrestricted German submarine warfare was destroying US ships and killing US passengers. The Americans were also angry at the Zimmerman Telegram, in which Germany asked Mexico to attack the US.
The Zimmerman Telegram.
New Mexico.
Mexico City
Faulty intelligence reports stating that Germany was supplying Mexico with weapons to attack the US (see Invasion of Veracruz).Pancho Villa's attack on Columbus, New Mexico (see Punitive Expedition).
Arthur Zimmerman (1864 - 1940)
Zimmerman sent a telegram to Mexico to try and convince Mexico to attack the US with the help of Germany
The Brittish revealed a telegram to the Americans : Mexico would attack the US if the US should attack the Germans. Finally the Mexicans did not attack the US due to the lack of surprise and the Americans engaged in WW2.
The Zimmerman Telegram qualifies as such.
You've just asked something like 'What is the address of Citibank in the US'.
The Zimmermann telegram was actually intercepted and decoded by the British, then given to the US. In it Mexico was promised the return of Texas, Arizona and New Mexico if they would join Germany.