The fourth Republic of Korea () was the government of South Korea from November 1972 to March 1981. The Fourth republic was founded on the approval of the Yushin Constitution in the 1972 constitutional referendum, codifying the de facto dictatorial powers held by President Park Chung-hee, and succeeding the third republic. Park and his Democratic Republican Party ruled under the centralized and authoritarian Yushin System until the assassination of Park on 26 October 1979. The Fourth Republic entered a period of political instability under Park's successor, Choi Kyu-hah, and the escalating martial law declared after Park's death. Choi was unofficially overthrown by Chun Doo-hwan in the coup d'état of December Twelfth in December 1979, and began the armed suppression of the Gwangju Democratization Movement against martial law. Chun launched the coup d'état of May Seventeenth in May 1980, establishing a military dictatorship under the National Council for Reunification and dissolving the National Assembly, and was elected president by the council in the August 1980 presidential election. The Fourth republic was dissolved on the adoption of a new constitution in March 1981 and replaced with the Fifth Republic of Korea. History Background Park Chung-hee had served as the leader and de facto dictator of South Korea since July 1961, coming to power two months after leading the May 16 coup which overthrew the Second Republic of Korea. Park and his supporters established the Supreme Council of National Reconstruction, a provisional military junta government that prioritized the economic development of South Korea, but faced strong pressure from the United States to restore the civilian government. In 1963, Park abdicated from his military position to run as a civilian in the October 1963 presidential election, defeating the incumbent President Yun Posun. The Third Republic of Korea was inaugurated two months later in December and presented as a return to civilian government under the National Assembly. In reality, it was a continuation of Park's military dictatorship, as the government was predominantly members of the Supreme Council, and the National Assembly was dominated by his Democratic Republican Party. Park won re-election in the 1967 presidential election, and the National Assembly passed a constitutional amendment that allowed him to serve a third term, which he narrowly won in the 1971 presidential election against Kim Dae-jung of the New Democratic Party. Park's popularity began to decline in the early 1970s, and he faced growing domestic opposition from