(Bloomberg) -- Singapore ruling party stalwart Tharman Shanmugaratnam will run for the largely ceremonial role of president after more than two decades as a key policymaker in the city-state.

The former deputy premier informed Prime Minister Lee Hsien Loong on Thursday he will step down from his positions in Cabinet and resign from the ruling People’s Action Party to contend. He will also leave his posts as chairman of the central bank and deputy chairman of sovereign wealth fund GIC Pte among others.

Tharman said he will leave on July 7. In a letter to Lee, he called it a “difficult decision” after 22 years in politics. In his reply, Lee described Tharman’s departure from Cabinet and the party as “a heavy loss.”

President Halimah Yacob last month announced she won’t stand for re-election when her term ends next quarter. While the prime minister runs the government, the president holds some powers such as the right to veto spending bills or government requests to draw on past reserves, which the administration resorted to during the pandemic to shore up the budget. 

The president, whose term lasts for six years, also signs off on key civil service appointments. 

Singapore’s constitution was amended in 1991 to allow citizens to vote for a president. Rules state that a presidential candidate must be an independent before nomination day, though those who were eventually elected to the office had previous affiliations with the ruling People’s Action Party or its administration.

“I believe that I can now best serve Singapore not in politics, but in a different role that has to be above politics,” Tharman said in his letter to Lee. If elected, “I will also work to the best of my abilities to project Singapore’s interests and voice of reason in an increasingly turbulent world.”

Tharman’s experience includes nine years as minister for finance, while he’s also credited with introducing major reforms as education minister aimed at achieving a more flexible system of meritocracy. 

The 66-year-old was first elected member of parliament in 2001 and has been chairman at the Monetary Authority of Singapore since 2011. Presently, he serves as coordinating minister for social policies, and advises Lee on the economy.

Inflation remains a threat in Singapore, and has become a political issue especially as housing costs stay hot. A still-tight labor market, especially for sectors like food & beverage, have many businesses lobbying for a loosening of foreign-worker restrictions while the government has pushed digitization and hire-local policies.

“As a member of my team, he has worked hard to build a more inclusive society, and to improve wages and create better jobs for Singaporeans,” Lee wrote in a Facebook post Thursday. “Tharman made significant contributions to strengthen our social mobility escalator, as well as what he called our social safety ‘trampoline.’”

A vote — due by September — may signal the public’s mood ahead of a parliamentary general election that must be called by November 2025.

Tharman is first to state he will contest for president. Lee Hsien Yang, the estranged younger brother of Prime Minister Lee, said in March he would consider running for the position, though several lawyers and academics quoted by the local Straits Times newspaper earlier this year questioned if he would meet the eligibility criteria.

A certificate of eligibility is required before a person can be nominated to run for president, and candidates must fulfill a set of criteria before they are issued one. In 2017, only Halimah received the certificate while four were issued in 2011.

Criteria include having held high office in the public sector or having served as chief executive of a large business. Some 50 public service positions would be eligible, as well as leaders of more than 1,200 companies in the city-state, Minister-in-charge of the Public Service Chan Chun Sing told Parliament last month.

“It remains to be seen if any potential opposition candidate can meet the requirements to run as well as not be deterred by the popularity that Tharman presents in the race,” said Nydia Ngiow, Singapore-based managing director at strategic policy advisory firm BowerGroupAsia.

--With assistance from Michelle Jamrisko.

(Adds comments from Tharman, pime minister from third paragraph)

©2023 Bloomberg L.P.