\( \begin{array}{ll}\text { Why did the U.S. get into the war? Franz Ferdinand Assass } \\ & \text { - Zimmermann Telegram- } \\ \text { - Lusitania- } \\ \text { - Unrestricted Submarine Warfare- }\end{array} \)

To understand why the U.S. entered World War I, we can analyze several key events and factors that contributed to this decision: 1. **Assassination of Archduke Franz Ferdinand**: - The assassination of Archduke Franz Ferdinand of Austria-Hungary on June 28, 1914, was a significant catalyst for the war. It set off a chain reaction of alliances and conflicts in Europe, leading to the outbreak of World War I. While this event did not directly involve the U.S., it created a global environment of tension and conflict. 2. **Zimmermann Telegram**: - In January 1917, British intelligence intercepted a secret communication from German Foreign Minister Arthur Zimmermann to Mexico. The telegram proposed a military alliance between Germany and Mexico in the event that the U.S. entered the war against Germany. Germany promised to support Mexico in reclaiming territories lost to the U.S. (Texas, New Mexico, and Arizona). The revelation of this telegram to the American public outraged many and increased anti-German sentiment. 3. **Sinking of the Lusitania**: - The British ocean liner RMS Lusitania was sunk by a German U-boat on May 7, 1915, resulting in the deaths of 1,198 passengers, including 128 Americans. This incident raised public outrage in the U.S. and contributed to the growing anti-German sentiment. Although the U.S. did not enter the war immediately after this event, it heightened tensions between the U.S. and Germany. 4. **Unrestricted Submarine Warfare**: - In early 1917, Germany resumed its policy of unrestricted submarine warfare, which meant that German U-boats would attack any ship, including civilian and neutral vessels, without warning. This policy led to the sinking of more American ships and the loss of American lives, further pushing the U.S. toward war. The most notable incident was the sinking of the American merchant ship SS Algonquin in March 1917. In summary, the combination of the assassination of Franz Ferdinand, the Zimmermann Telegram, the sinking of the Lusitania, and the policy of unrestricted submarine warfare created a situation where the U.S. felt compelled to enter World War I in April 1917. Each of these factors contributed to a growing sentiment in favor of joining the Allies against the Central Powers.