On 17 May 1980, Chun placed the entire country under martial law and disbanded the National Assembly. Many politicians were arrested, including liberal politician Kim Dae-jung. Kim was later sentenced to death in spite of protests from the United States. Later, Chun changed Kim's sentence in return for U.S. support. Protests across the nation became smaller. However, very violent prostests happened in Gwangju. Protestors Lootinglooted government building. They armed themselves with stolen guns and military jeeps. Protestors killed a couple of policemen and started of violent protest against the government. A couple of hundreds of protestors and some thirty soldiers were killed in the Gwangju. Choi resigned in August, and Chun was elected his successor by the National Conference for Unification, the South Korean electoral college, in September. In February 1981, Chun was elected president under a revised constitution as the candidate of the Democratic Justice Party (later renamed Democratic Republican Party). 