What key event led to the creation of the Zimmerman Telegram?

The Zimmerman Telegram was a significant diplomatic communication sent in January 1917 from Germany to Mexico. The creation of this telegram was primarily a response to escalating tensions between Germany and the United States, particularly due to German U-boat attacks on American ships. By 1917, these attacks had intensified, leading to significant American public outrage and escalating calls for the U.S. to enter World War I.

In the telegram, Germany proposed a military alliance with Mexico in the event that the United States entered the war against Germany. This was a strategic move intended to distract and weaken the U.S. by opening another front in the conflict. The revelation of the telegram further inflamed American sentiment against Germany and played a crucial role in the U.S. decision to join the war.

The other options do not directly link to the creation of the Zimmerman Telegram. The assassination of Franz Ferdinand was an earlier event that ignited the war but did not specifically lead to the telegram. The Treaty of Versailles and the formation of the League of Nations occurred after the Zimmerman Telegram and were results of the war rather than causes of its escalation. Thus, the German U-boat attacks on American ships were the catalyst that prompted Germany to reach out to Mexico, leading to the creation