A violent conflict between U.S.-backed South Korea and China-backed, Soviet-controlled, North Korea, the three-year-long Korean War was the first major clash between democratic and communist forces. Although China had some direct military involvement in the conflict, contrary to common knowledge, China was also a major geopolitical player in determining the length and repercussions of the war. Chinese intervention in the Korean War was instrumental in maintaining the two-state division on the Korean Peninsula.

The Korean War began with the invasion of South Korea by North Korea in June of 1950, and the United States entered the war one month later. Following the United States’ victory as a result of the Inch’on landings on September 15, 1950, Seoul was reclaimed by South Korea, and the North Koreans – fearing further losses – contacted Beijing with a request for military aid. As U.S. General MacArthur approached the 38th parallel with intention to cross it into antebellum North Korean territory, China announced on October 3rd that if MacArthur crossed, China’s military would intervene on behalf of North Korea.

Despite this threat, U.S.-South Korean forces continued to push into North Korea until reaching the capital of Pyongyang on October 20th, and China followed through on its promise, joining the war just days later. The following months were characterized by clashes between Chinese and American forces, pushing the U.S. and South Korean troops back across the 38th parallel. With no side gaining ground for several months following the retreat, peace talks between the two sides began in February of 1951. After armistice talks continued to stagnate through 1952, U.S. President Dwight Eisenhower hinted that he would authorize the use of nuclear weapons against China if an agreement could not be reached soon.

The presence of ten nuclear-configured B-29 bombers that had been stationed in the Pacific region by President Harry Truman in July of 1950 (with the intention of deterring China from entering the Korean War) punctuated Eisenhower’s warning, and peace talks continued alongside the militant conflict until a cease-fire was negotiated on July 27, 1953.

Even though the United States and China made peace following the Korean War, China did not forget the “nuclear blackmail” by President Eisenhower and other American military leaders, and thus began its own efforts to develop a domestic nuclear weapons program.