The armed conflict in Korea, which began in 1950, lasted three years and claimed the lives of millions of Korean soldiers and civilians on both sides, hundreds of thousands of Chinese soldiers, and more than 36,000 U.S. soldiers. However, the United States never formally declared war on North Korea, China, or the Soviet Union. And, although the U.S. military led the United Nations’ expeditionary force, its involvement was tied only to a UN Security Council resolution, because the UN itself cannot declare war. Consequently, the conflict in Korea did not technically constitute a war.