Singapore Democratic Alliance

The Singapore Democratic Alliance (abbreviation: SDA) is a political coalition between Singapore Malay National Organization (PKMS) and Singapore Justice Party (SJP). The SDA was formed in 2001 and initially consisted of four political parties, PKMS, SJP, National Solidarity Party (NSP) and Singapore People's Party (SPP).
As of 2023, only SJP and PKMS are in the alliance.
SDA was first established in 2001 by Chiam See Tong as he wanted to provide a common grouping under which different opposition parties could stand as a political coalition in elections against the ruling People's Action Party (PAP). The alliance initially consisted of his party SPP, NSP, SJP and PKMS. It was the first coalition to be formed in post-independence since 1963, after the now-defunct Singapore Alliance Party. Chiam became the first chairman of SDA. The logo of SDA is a star and four interlocking circles.
In the 2001 general election, SDA contested a total of thirteen seats consisting of three SMCs (Bukit Timah, Chua Chu Kang, Potong Pasir), and two 5-member GRCs (Jalan Besar, Tampines). In the 2006 general election, SDA contested a total of twenty seats consisting of four SMCs (Chua Chu Kang, MacPherson, Potong Pasir, Yio Chu Kang), two 5-member GRCs (Jalan Besar, Tampines), and one 6-member GRC (Pasir Ris-Ponggol). SDA managed to retain the Potong Pasir SMC seat under Chiam through both elections and obtained one NCMP seat under Steve Chia in the 2001 election.
In 2007, the NSP pulled out from the SDA in the hope of rejuvenating their party. In 2009, Chiam spoke of the possibility of having Reform Party (RP) to join the SDA. Later in 2010, Kenneth Jeyaretnam, the secretary general of Reform Party (RP), met with Chiam and discussed for RP to join SDA. RP had set out a list of 11 conditions which Chiam and his wife, Lina Loh, mostly agreed to. However, the rest of the leadership of SDA voted not to make a decision on the list of conditions. The discussion by the SDA council was leaked to the press and as a result, Jeyaretnam decided not to join the SDA.
In October 2010, Chiam replaced SDA's secretary general, Desmond Lim Bak Chuan, with Mohamad Hamim Aliyas during a central executive committee meeting of the SPP. SPP founder and chairman Sin Kek Tong said that Chiam's move was due to Lim's opposition to RP joining the SDA. However, in a SDA council meeting held shortly after, the council rejected the decision of Chiam, and Lim remained as the secretary general.
On 2 March 2011, SPP withdrew from the coalition, following the decision by the SDA council to relieve Chiam as chairman, citing frequent "no-shows" at the alliance meetings. Following the pullout, SDA became a two-party alliance consisting of PKMS and SJP. The chairperson was later succeeded by SJP leader Desmond Lim.
Events that followed the separation of Chiam's SPP from SDA saw the waning of the alliance, where they fell short on winning any of the subsequent elections. In the 2011 general election, the SDA, NSP (which fielded a large slate of candidates), and SPP were unsuccessful: Lim became the only candidate forfeiting his electoral deposit (S$16,000) in the only three-cornered contest in the newly formed Punggol East SMC (a ward carved out from the neighbouring Pasir Ris-Punggol GRC, which the alliance also contested); and SDA members who joined as independents contesting in Tanjong Pagar GRC (the election's only uncontested constituency) were disqualified on nomination day.
In the 2013 by-election at Punggol East SMC, Lim contested again, but later conceded defeat during vote counting; ultimately, he garnered only 0.53% of the valid votes cast for the election, resulting him as the second candidate in history (after United People's Front candidate Harbans Singh) to have his deposit forfeited on both times, and consequently set its record-worst score for a candidate in post-independence Singapore. In the 2015 general election, SDA fielded their only team of six in Pasir Ris–Punggol GRC, but with no success.
Leading up to the 2020 election, four political parties: Singaporeans First, People's Power Party, Reform Party and Democratic Progressive Party, proposed to form an alliance of their own. Subsequently, the four parties decided to apply to join the SDA, but the go-ahead did not materialize. SDA had contested the 2020 election, marked as Lim's last election leading the SDA. While the party only contested Pasir Ris-Punggol GRC, a three-cornered contest arose with the participation of a third political party, Peoples Voice. This was the second time in Singapore's election history that a multi-cornered fight had taken place in a GRC (the first being 1992's by-election under Marine Parade GRC). SDA scored 23.67% of the votes while PV ended up losing their deposits after garnering 12.18%.
On 11 March 2025, Lim announced that he had reversed his earlier decision to step down as chairman of the SDA.
Due to an alliance, the number of respective seats and the results combined from the four parties (NSP, SJP, SPP and PKMS) were reflected in the table. NSP and SPP left after the 2006 general election.