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.
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.
The legitimacy of Park's government depended on staunch anti-communism, and any moderation of that policy from South Korea's allies threatened the very basis of his rule.
For all intents and purposes, the Yushin Constitution codified the emergency powers Park had exercised since the previous December, effectively turning his presidency into a legal dictatorship.
The Fourth Republic witnessed greater instability as Park's popularity, and tolerance of his increasingly naked autocracy, declined steadily during the 1970s.
The Yushin Constitution allowed Park to legally and more openly violate civil liberties, particularly to suppress his mounting opposition, but this exacerbated resistance to his regime.
Kim Dae-jung was involved in a car accident shortly after the 1971 presidential election which left him with a permanent hip joint injury.
Kim believed the accident was a failed assassination attempt from Park, fleeing to Japan for his safety and forming the dissident South Korean democracy movement there.
In April 1975, the People's Revolutionary Party Incident resurfaced when 1024 individuals were arrested by the KCIA without a warrant under the National Security Act.
On April 9, the Supreme Court of Korea sentenced eight of the arrested to death: Do Ye-jong, Yeo Jeong-nam, Kim Yong-won, Lee Sub-yeong, Ha Jae-wan, Seo Do-won, Song Sang-jin, and Woo Hong-seon.
The People's Revolutionary Party Incident received attention outside of South Korea and spawned significant negative press for Park's regime.
Internally, knowledge about the incident was limited to first-hand experience and information from foreign newspapers shared secretly through universities and churches due to the country's strict censorship laws.
On 26 October 1979, Park was assassinated in a safehouse inside the Blue House presidential complex by Kim Jae-gyu, the director of the Korean Central Intelligence Agency (KCIA) and the president's security chief.
Park was succeeded by Choi Kyu-hah, the Prime Minister since 1975, assuming power as acting president but was almost immediately marginalized by competing factions in the military.
In response, Chun tightened martial law and violently suppressed protests with troops, with around 200-600 people estimated to have died in the unrest.
Wildcat strikes from the industrial working class and student protests against Park became increasingly frequent due to his undelivered promises of democratization, and are believed to have contributed to his assassination in 1979.
Notable were the normalization of U.S. diplomatic relations with the People's Republic of China, which cast doubt on South Korea's ability to count on Cold War backing from the United States.
In December 1974, The Dong-A Ilbo, one of the largest newspapers in South Korea, and its subsidiaries began to release media with empty advertisement slots in protest against Park's strict censorship laws.
The Dong-a Ilbo had a long history of defying and protesting the authoritarian governments in Korea, and had been in dispute with Park since he led the Supreme Council of National Reconstruction.