Fifth Republic of Korea

Park Chung Hee had served as the leader of South Korea since July 1961, during which he was a de facto military dictator and maintained his near-absolute power through legal and illegal channels. Park originally came to power as Chairman of the Supreme Council of National Reconstruction two months after the May 16 coup (which he had led) overthrew the Second Republic of Korea. The Supreme Council established a provisional military junta government that prioritized the economic development of South Korea, but faced strong pressure from the United States to restore civilian rule. 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 and inaugurating the Third Republic of Korea two months later in December. The Third Republic was presented as a return to civilian government under the National Assembly, but in reality was a continuation of Park's military dictatorship and the government was predominantly members of the Supreme Council. 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 won in the 1971 presidential election against Kim Dae-jung. In December 1971, Park declared a state of emergency. On 10 October 1972, Park launched a self-coup known as the October Restoration, dissolving the National Assembly, suspending the constitution, and declaring martial law across the country. Park commissioned work on a brand new constitution, known as the Yushin Constitution, which essentially formalized his long-held dictatorial powers and guaranteed him as president for life. On 21 November 1972, the Yushin Constitution was approved in the 1972 South Korean constitutional referendum with 92.3% of the vote and came into force, dissolving the Third Republic and establishing the Fourth Republic of Korea.

Park's popularity in South Korea declined during the 1970s, as the economic growth of the 1960s began to slow and the public became more critical of his authoritarianism. On 26 October 1979, Park was assassinated at a safehouse by Kim Jae-gyu, the director of the Korean Central Intelligence Agency (KCIA), causing political turmoil in South Korea. Park's successor, Choi Kyu-hah, was an ineffective president whose authority was largely ignored by the political elite. In December, Major General Chun Doo-hwan, the Chairman of the Defense Security Command and a former military colleague of Park, overthrew Choi's government in the Coup d'état of December Twelfth, and over the next few months gained control over most government apparatuses. In May 1980, Chun launched the Coup d'état of May Seventeenth establishing a military dictatorship under National Council for Reunification and declared martial law. Chun violently suppressed the subsequent Gwangju Uprising democracy movement against his rule in Gwangju, during which 200-600 people may have died. In August, Choi resigned and Chun was elected President in the 1980 presidential election by the National Council, running unopposed and winning 99.37% of the vote. In October, Chun abolished all political parties and established his own, the Democratic Justice Party, which was effectively a re-branding of Park's Democratic Republican Party that ruled South Korea since 1963. Soon afterwards, a new constitution was enacted that, while far less authoritarian than Park's Yusin Constitution, still gave fairly broad powers to the president.

The Fifth Republic of Korea was formally inaugurated on 3 March 1981, when Chun was inaugurated as President after being re-elected in the February 1981 presidential election.

Although Chun gradually dismantled the highly centralized government structures set up by Park, his presidency was plagued by public outrage over his reaction to the Gwangju Uprising in 1980. The killings had consolidated momentum of nationwide support for democracy, and many people protested for faster democratization. Chun reorganized the government system and created numerous new ministries, but South Korea remained a de facto one-party state under the Democratic Justice Party, and most elections during this era were not considered legitimate. Nevertheless, Chun had far less power than Park, and with few exceptions his rule was somewhat milder.

In the mid-1980s, Chun began to release political prisoners arrested during his rise to power. In 1985, the New Korea and Democratic Party (NKDP) was founded as the successor of the New Democratic Party, including notable opposition leaders Kim Dae-jung and Kim Young-sam, and campaigned on a focus on greater democratic rights.[2] The NKDP became the opposition in the National Assembly after strong success in the 1985 South Korean legislative election, with only 6% fewer votes than Chun's Democratic Justice Party. Reportedly, the NKDP's electoral success shocked and infuriated Chun. However, in 1986 the NKDP experienced internal ideological conflicts over the severity of opposition to Chun, and in 1987 Kim Young-sam's faction split to form the Reunification Democratic Party.

In January 1987, the death of Park Jong-chul caused a flare in the democratization movement and sparked widespread protests. Bak, a student at Seoul National University and democracy movement activist, died from causes related to police torture after being arrested at a protest. In June 1987, the death of Lee Han-yeol, a protester killed by a police tear gas grenade at one of the demonstrations following Bak's death, caused the democracy movement put unrelenting pressure on Chun. The protesters demanded elections to be held, as well as instituting other democratic reforms, including direct presidential elections. On June 10, Chun announced his choice of Roh Tae-woo as the next president, which was opposed by the protesters. However, unwilling to resort to violence before the 1988 Olympic Games and believing Roh could win legitimate elections due to divisions within the opposition, Chun and Roh acceded to the key demands of direct presidential elections and restoration of civil liberties. On 16 December 1987, Roh won the 1987 presidential election with 36.6% of the vote, the first honest national elections in South Korea in two decades. Three days later on 19 December, a new highly-democratic and liberal constitution came into effect, dissolving the Fifth Republic and establishing the current Sixth Republic of Korea. Chun finished out his term and handed the presidency to Roh on 25 February 1988.