Arthur Zimmermann 1864 - 1940
Arthur became famous for the Zimmermann Note, which was his telegram to the German diplomat in Mexico, giving the latter permission to propose to Mexican President Venustiano Carranza an alliance between Mexico and Germany against the United States.
The note mentioned that the Germans would aid Mexico in recovering Mexico's "lost territories Texas, New Mexico, and Arizona."
The Germans were struggling in the fight of World War I. They knew they would have a big military advantage if they were to employ unrestricted submarine warfare. But at the same time doing so would provoke the United States to enter the war on the side of Germany's enemies, the Allies.
Zimmermann figured it would be therefore a good idea if the US were perhaps distracted by a war with Mexico or Japan, or preferably both. He sent the message on January 16, 1917.
The telegram was intercepted and decoded, however, and made US President Woodrow Wilson rub his eyes twice. Five weeks later the US declared war on Germany, thus entering Word War I.