On 25 June 1950, seven divisions of highly trained and well-equipped North Korean troops crossed the 38th parallel, the boundary between North and South Korea, initiating a full-scale invasion of South Korea. The North Korean People's Army (NKPA), numbering over 90,000 soldiers and bolstered by Soviet-supplied artillery and tanks, aimed to swiftly overrun the South Korean defenses and unite the Korean Peninsula under communist rule.

The ill-prepared and outnumbered South Korean Army, known as the Republic of Korea Armed Forces (ROKAF), was caught off guard by the sudden attack. Despite valiant efforts to repel the invaders, the South Korean defenders were pushed back, with the North Koreans capturing the capital city of Seoul within just three days of the invasion.

In response to the North Korean aggression, the United Nations Security Council unanimously condemned the attack and called for an immediate cessation of hostilities. Suspecting potential involvement and encouragement from the Soviet Union and Communist China, U.S. President Harry S. Truman made the decision to deploy American air, ground, and naval forces to support the combined United Nations forces in their efforts to assist the Republic of Korea's defense. General Douglas MacArthur was appointed by President Truman to serve as the Commanding General of the United Nations Command (UNC). The United States, under President Harry S. Truman, promptly intervened on behalf of South Korea, leading a coalition of 21 member nations under the United Nations Command (UNC). The UN forces were primarily composed of US troops, along with smaller contingents from other countries such as the United Kingdom, Canada, Australia, and Turkey.

The ensuing conflict, known as the Korean War, proved to be far from the quick victory envisioned by the North Koreans. The war raged on for more than three years, marked by intense fighting, massive casualties on both sides, and the involvement of major world powers, including the United States, the Soviet Union, and China.

The battle lines fluctuated dramatically throughout the course of the war, with the UNC forces, led by General Douglas MacArthur, launching a daring amphibious landing at Inchon in September 1950, which successfully cut off the North Korean supply lines and turned the tide of the war in favor of the South. However, the subsequent entry of Chinese forces into the conflict in October 1950 once again shifted the balance of power, leading to a protracted stalemate.

In October, with strong encouragement from the United States Government, the United Nations approved the advance of UN forces across the 38th parallel into North Korean territory, with the goal of unifying the country under a non-communist government. Despite clear warnings from the Chinese Government, the United Nations forces continued their push toward the Yalu River, which marked the border between North Korea and Manchuria. General MacArthur, dismissing the significance of initial Chinese attacks in late October, ordered the UNC to launch an offensive to reach the Yalu. In late November, Chinese forces launched a full-scale counter-offensive, driving the UNC back in disarray south of the 38th parallel and capturing the South Korean capital, Seoul.

Top photo: 15 September 1950: The invasion of Inchon. Source: War History Network license and archives.

Bottom photo: Korea, 4 Sepptember 1951: F4U's Corsairs returning to the flight deck of the USS Boxer from a combat mission over North Korea. Aircraft in the next strike are about to be launched from the carrier flight deck. Source: War History Network license and archives.

By early 1951, the Chinese offensive had lost its momentum, and the UNC, reinforced by the rejuvenated U.S. 8th Army under the command of General Matthew B. Ridgway, recaptured Seoul and pushed back to the 38th parallel. From July 1951 until the end of the war, the battle lines remained relatively stable, and the conflict reached a stalemate. The Truman Administration abandoned its plans to reunify North and South Korea, opting instead to pursue limited objectives to avoid potentially escalating the conflict into a third world war involving China and the Soviet Union. In April 1951, when General MacArthur publicly challenged the Truman Administration's handling of the war, the President concluded that "MacArthur is unable to give his wholehearted support to the policies of the United States Government" and subsequently relieved him of his command, replacing him with General Ridgway.

Throughout the course of the Korean War there were numerous victories and setbacks on both sides. Despite initial success by North Korea and China's intervention on their behalf, the tide of the war eventually turned in favor of the UN forces. The introduction of modern weaponry such as jet fighters and helicopter gunships played a significant role in shifting the balance of power. The Korean War also saw major advancements in medical technology and techniques, with advancements like mobile surgical units and blood transfusions saving countless lives on the battlefield. However, despite these developments, the war was marked by intense fighting and brutal conditions, with both sides committing atrocities against prisoners of war and civilians.

Fulfilling a campaign promise, President-elect Dwight D. Eisenhower visited Korea on 2 December 1952. After meeting with troops, their commanders, and South Korean leaders, and receiving briefings on the military situation, Eisenhower concluded, "we could not stand forever on a static front and continue to accept casualties without any visible results. Small attacks on small hills would not end this war." President Eisenhower sought to end the hostilities in Korea by employing a combination of diplomacy and military pressure. On 27 July 1953, seven months after Eisenhower's inauguration as the 34th President of the United States, an armistice was signed, effectively ending organized combat operations and leaving the Korean Peninsula divided along the 38th parallel, much as it had been since the end of World War II.

The United Nations' "police action" in Korea successfully prevented North Korea from imposing its communist rule on South Korea. Moreover, the United States' intervention in the conflict demonstrated America's resolve to confront aggression, strengthened President Eisenhower's position in Europe as he sought to organize European military defense under the North Atlantic Treaty Organization (NATO), and ensured that the United States would pursue the military buildup outlined in the pivotal Cold War document, National Security Council Policy Paper No. 68.

Bibliography

Halberstam, David. The Coldest Winter: America and the Korean War. New York: Hyperion, 2007.

Hammel, Eric. Chosin: Heroic Ordeal of the Korean War. Havertown: Casemate, 2019.

"Korean War | Eisenhower Presidential Library." Eisenhower Presidential Library. https://www.eisenhowerlibrary.gov/research/online-documents/korean-war.

"The Korean War and Its Origins." Welcome to the Harry S. Truman Presidential Library and Museum | Harry S. Truman. https://www.trumanlibrary.gov/library/online-collections/korean-war-and-its-origins.

Sides, Hampton. On Desperate Ground: The Marines at The Reservoir, the Korean War's Greatest Battle. New York: Doubleday, 2018.