Final answer:
The last time Congress declared war was in WWII.
Step-by-step explanation:
The last time Congress declared war was in WWII. On December 8, 1941, following the attack on Pearl Harbor, the United States declared war on Japan. In response, Germany and Italy declared war on the United States, and the United States reciprocated. This marked the official entry of the United States into World War II. Although the United States has been involved in several military conflicts since then, Congress has not formally declared war since WWII.
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