2011 On 27 May 2011, 20 days after the recent general election, Tan was the first candidate to seek candidacy for the forthcoming
Presidential Election; he resigned from PAP earlier that month prior to the announcement (per the constitution, candidates running for the presidential election must be a
nonpartisan, independent candidate, and should not affiliate or to represent to any political party). On 22 July 2011, Tan submitted the presidency forms. Ahead of the nomination day (due to be held on 17 August), despite anticipation for a strong contest against the other potential rivals who also announced their candidacy (former
Deputy Prime Minister Tony Tan, and
NTUC Income Chief Executive Officer
Tan Kin Lian), he filed his applications on 22 July, and on 11 August, was one of the four candidates (the aforementioned three, plus former
Singapore Democratic Party candidate
Tan Jee Say) to be granted the Certificate of Eligibility, an item required to complete their nominations during Nomination Day. The four-cornered fight marked only the second presidential election in history (the first was in
1993) with a contest, as the two preceding presidential elections (
1999 and
2005) were both
uncontested walkovers. Tan stated that he would promote
multiracialism, if elected. Controversy erupted shortly after Tan declared his interest in the presidency. It was revealed that in a
Straits Times article dated back in 1987, Tan had spoken regarding the Singaporean government's controversial
Operation Spectrum while he was in Parliament, which saw 22 young Roman Catholic church and social activists and professionals detained without trial. He addressed, in his capacity as Feedback Unit chief, that most Singaporeans had accepted the reasons of the government and the
Internal Security Department for the detention. He also reported that certain "solid citizens" were sceptical of the detention. On 4 June 2011, Tan's
Facebook administrator cited that as posts on his page about the incident were running contrary to what law courts have ruled, the risk of being sued for defamation was open to both hosts of the site and people behind the posts alike, as such, "(they) are obliged to remove posts that run contrary to what the law courts have ruled." In the presidential candidate broadcast, Tan said, "The President must be above politics" and that "he must not be a proxy to be any political party", as "his interest must be national, not with a political agenda in mind". He also proposed that the government and the Prime Minister's Office be separated as "this familiarity attracts unwanted suspicion of undue influence". He emphasised that the separation is a symbolic move required to reassure the people that they are independent of each other. Tan also proposed an annual statement for greater transparency for Singaporeans to better understand the president's activities and ideas in unifying Singapore. The statement also touches on Singapore's reserves and the rationale behind the appointment or vetoing of civil servants. Tan's campaign slogan was "Think Singaporeans First", a reference to his 1999 debate on the need to prioritise Singaporeans first when faced with prevailing foreign talent policy. On 27 August, Singapore went to choose their seventh and newly elected candidate. About five hours after polls closed, at 1.23am, Tan called Election Department for an
Election recount; due to a narrow margin with less than 2% between the top two highest candidates (the other was Tony Tan), ELD approved Tan's request, and vote counting went on for around three hours before the results were finalised. At 4.10am, the final results saw Tan Cheng Bock losing the election marginally to Tony Tan by a 0.35% margin (7,269 votes); Cheng Bock garnered 737,128 (34.85% out of the 2,115,118 valid) votes, while Tony garnered 744,397 votes (35.20%). Tan requested a second counting of votes and accepted the results and tried to stand again for
2017 Singaporean presidential election. However, changes made to the criteria of candidates rendered him ineligible. In a congratulatory Facebook post published on 13 September 2017, Tan said that the elected
Halimah Yacob would assume "...the most controversial presidency in the history of Singapore."
2017 In March 2016, Tan declared his intention to run again for president in
the next presidential election, which had to be held within the next 17 months. In September 2016, the eligibility criteria for the elected presidency was revised to include the "reserved election" (an election made exclusive for one particular race; in the case, Malay candidates), and were passed by the
Constitution in November 2016, eventually preventing Tan from running in the election. In May 2017, three months before the elections, Tan filed a constitutional challenge to the
High Court, to determine whether it is correct to set the election as a reserved election under the newly introduced amendments to the Elected Presidency, and whether
Wee Kim Wee (the fourth Singapore's president) is counted as one six-year term since the constitution for the elected presidency was instated in 1991, but the High Court's Justice Quentin Loh dismissed his challenge, providing an explanation that "Article 164(1)(a) provides for Parliament to specify the first term of office of the President to be counted under Art 19B(1)" ("First Term"). Tan later appealed to the
Court on 31 July, but the court of the five judges unanimously dismissed his appeal on 23 August, ruling that the Parliament has their full discretion to set the First Term, which President Wee was counted as one term of Presidency. The election ended with a
walkover after former
Parliamentary Speaker Halimah Yacob became the sole candidate to be granted the Certificate of Eligibility, and was inaugurated on 14 September. After the nomination day, he, along with potential candidates such as Farid Khan and Salleh Marican, also congratulated
Halimah on her victory.
2023 On 27 August 2023, Tan Cheng Bock, acting in his personal capacity, endorsed Tan Kin Lian in the
2023 presidential election. Tan had been his rival in the 2011 presidential election. ==Charity work==