Final answer:
Acts of German aggression, such as the sinking of the RMS Lusitania and the resumption of unrestricted submarine warfare, caused U.S. opinion to turn against Germany.
Step-by-step explanation:
U.S. opinion turned against Germany due to Acts of German aggression. One major event that caused this shift in opinion was the sinking of the British passenger ship RMS Lusitania by a German U-boat in 1915, resulting in the death of 128 Americans. This act of aggression brought widespread condemnation and led to a negative public opinion towards Germany.
Another significant factor was Germany's resumption of unrestricted submarine warfare in 1917, which resulted in the sinking of American merchant ships. These actions further fueled anti-German sentiment among the American population.
Economic interests also played a role in shaping U.S. opinion against Germany. As Britain and France were major trading partners of the United States, the American economy suffered from Germany's aggression against these countries, leading to a negative view of Germany among the American public.
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