When the government of Britain presented the administration of U.S. President Woodrow Wilson with what became known as “the Zimmerman Telegram” in 1917, it created a quandary for the U.S. government. The message appeared to be a proposal from Germany to Mexico to form an alliance against the United States, with Germany offering Texas, New Mexico, and Arizona to Mexico in the event of a victorious outcome. But was it genuine?
Public opinion in the United States at the time was staunchly isolationist. Wilson—who had been reelected in 1916 under the slogan “He kept us out of war!”—was one of the most antiwar presidents in U.S. history. David Milne wrote in his seminal book Worldmaking that after the United States received the telegram: