Final answer:
Germany's actions finally forced the United States to enter World War II.
Step-by-step explanation:
Germany was the country whose actions finally forced the United States to enter World War II. On December 7, 1941, Japan attacked the US naval base at Pearl Harbor which led to the US declaring war on Japan. As a result of the Axis powers alliance, Germany, Italy, and Japan were all at war with the United States.
Learn more about Actions that led the United States to enter World War II