1. Korean War (1950-1953)
The Korean War began on June 25, 1950, when North Korean forces crossed the 38th parallel, invading South Korea. The United Nations, led by the United States, intervened to defend South Korea. Despite the extensive military engagement and significant casualties, neither side issued a formal declaration of war. The U.S. Congress authorized a ‘police action’ instead, raising constitutional questions and highlighting international uncertainties (nationalgeographic.com).
