The party was founded in 1980 by Chiam See Tong, who as Secretary-General became the party's first Member of Parliament (MP) in 1984 when he was elected as MP for Potong Pasir. At the 1991 general election, the party's best ever performance, two further SDP members, Ling How Doong and Cheo Chai Chen, were elected to Parliament giving the party a total of three MPs. However, Chiam fell out with the party's Central Executive Committee in 1993 and subsequently left the party in December 1996. He was succeeded by Chee Soon Juan, who has remained the Secretary-General since the SDP's Ordinary Party Conference in 1995. The party has since focused more on a liberal human rights agenda but has yet to secure parliamentary representation since 1997 general election.