* The German U-boat campaign: In 1915, Germany began to sink passenger and merchant ships in the North Atlantic without warning, killing many American citizens and causing severe economic losses. This was a direct attack on the United States, and it provoked widespread outrage.
* The Zimmerman Telegram: In the early months of 1917, the British intercepted and decoded a telegram from Germany to Mexico. In this telegram, Germany proposed that Mexico and the United States go to war against each other, with the German government promising to support and help Mexico recover territories lost to the United States in the Mexican-American War. This revelation exposed the German government’s duplicity and hostility towards the United States and increased support for the U.S. entry into the war.
* The Russian Revolution: In March 1917, the Russian czar was overthrown in a revolution, and a provisional government was established. This event inspired many Americans who wanted to join the war to help secure democracy around the world.
* The sinking of the Lusitania: In May 1915, a German U-boat sank the British ocean liner Lusitania, which was also carrying American passengers. The deaths of over 1,198 innocent passengers, including 128 Americans, caused widespread outrage in the United States and further eroded public support for neutrality.
* Propaganda: The American government and media mounted an aggressive propaganda campaign that portrayed the war as a noble and righteous cause, depicting Germany as a tyrannical menace and emphasizing the importance of American democracy and ideals. This propaganda helped sway public opinion in favor of intervention in the war.
These are just some of the reasons that led the United States to enter World War I.