Yun Po-sun
4th President (1960–1962), elected by the National Assembly under the parliamentary system after the April Revolution; resigned after the May 16 coup
After serving under Syngman Rhee as Mayor of Seoul and Minister of Commerce and Industry, he became an opposition politician and led the Old Faction of the Democratic Party. When the third constitutional amendment of 1960 introduced a parliamentary system, the National Assembly elected him president, though real power lay with Prime Minister Chang Myon. He resigned in 1962 after the May 16 Military Coup. He ran as the opposition candidate in the 1963 and 1967 presidential elections and lost to Park Chung-hee both times. Opposing the Yushin system, he joined the March First Democratic Declaration of 1976.