What events in 1916 and 1917 contributed to the impact the Zimmerman telegram would have on the American public?

In 1916, the sinking of the Lusitania and other attacks by German U-boats heightened anti-German sentiment in the U.S., setting the stage for increased public outrage. Additionally, the resumption of unrestricted submarine warfare by Germany in early 1917 further escalated tensions. The Zimmerman telegram, which proposed a military alliance between Germany and Mexico against the U.S., was intercepted in early 1917, amplifying fears of German aggression and swaying public opinion towards supporting entry into World War I. Together, these events created a climate of heightened alarm and nationalism, making the telegram's revelation particularly impactful.