What role did Japanese Emperor Hirohito play in the entry of the US into World War II?

Hirohito was Japan’s emperor during its military expansion across Asia and the Pacific, which increased tensions with the United States. Japan’s attack on Pearl Harbor in 1941 brought the US into World War II. Of these choices, “He oversaw Japan’s rapid territorial expansion” best describes his role; he did not lead an attack on the US mainland.

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