A Constitutional Commission will review three aspects of the Elected Presidency. Insight takes a look at each of them.
On the face of it, one way to ensure that a private sector candidate for the presidency has the executive capability needed today is simple - just tweak the numbers.
Currently, such a candidate must have served no less than three years as chairman or chief executive of a company with a paid-up capital of at least $100 million, or any other comparable position of seniority.
But that was made law 25 years ago and, as Prime Minister Lee Hsien Loong said last week in Parliament when suggesting a review of the qualifying criteria for candidates, inflation alone makes that $158 million today.
Lawyers and constitutional law experts The Sunday Times spoke to suggested increasing the paid-up capital threshold. This would reduce the pool of eligible candidates to only those who have more senior-level management experience for a post which, while largely ceremonial, has custodial responsibilities for Singapore's massive national reserves.
Public sector candidates, meanwhile, must have held key appointments like judges, ministers, permanent secretaries or heads of statutory boards.
Experts also suggested looking at whether other criteria should be written into law, such as requiring private sector candidates to have headed companies of a specific degree of complexity and suitability, for them to take on the role of the President.
But then again, some criteria are more qualitative than quantitative.
Former deputy prime minister and retired law minister S. Jayakumar, who was instrumental in drafting the law governing the Elected Presidency in the late 1980s, has written about the ideal type of candidate for the President.
This would be a respected elder statesman, a distinguished public officer or a successful corporate leader with the temperament to resolutely discharge his custodial duties, Professor Jayakumar wrote in his memoirs published last year, Be At The Table Or Be On The Menu.
"I recognise, however, that it is impossible to legislatively prescribe requirements to ensure that only such candidates can stand for President," he wrote.
It is a position he continues to hold today (see related story).
Experts said enshrining something in law beyond numbers - or even beyond words - is tricky.
For example, it is hard to see what wording could be inserted into the Constitution to define how complex a company needs to be before its CEO is seen as having the right level of expertise and experience to be a presidential candidate, said Singapore Management University constitutional law lecturer Jack Lee.
Referring to the high-level public committee that advises the President, he said: "At some stage, I think we need to trust the Council of Presidential Advisers (CPA) to do its job."
National University of Singapore constitutional law professor Thio Li-ann agreed, saying the President should have access to expertise from the CPA.
ABOUT THAT THRESHOLD
Still, in terms of identifying concrete criteria, PM Lee last week said: "They have to assess and decide on financial proposals which will involve billions of dollars."
He added that the number of $100 million companies has increased at least thirteen-fold since 1990, to more than 2,100.
Lawyer and Marine Parade GRC MP Edwin Tong said the threshold is "obsolete and outdated", as he made a call last Thursday in Parliament for it to be raised.
But former Attorney-General Walter Woon, now a law professor at NUS, said he is unconvinced it must be changed, calling $100 million a "purely arbitrary" figure.
He said: "The point was to have someone who had experience at the helm of a large company, so that he or she could understand enough about finance to be effective as a check on a profligate government. Even today, a $100 million company is still a very big business."
Constitutional law expert and NUS adjunct professor Kevin Tan said increasing the paid-up capital minimum may not necessarily refine the criteria for selection.
He said: "I reckon that anyone who can run a $100 million company can just as well run a $300 million company.
"To further tighten the requirements only serves to narrow the total number of possible presidential aspirants, nothing more. It does not necessarily mean you will get qualitatively better candidates."
Still, experts said the commission that will explore changes to the Constitution needs to look beyond mere numbers.
Mr Tong said: "Just because a candidate has been a CEO of a company with $x million paid-up capital or turnover does not necessarily make that person a suitable candidate for the office of the Elected President."
Candidates should be familiar with the constitutional limits on the Elected President and demonstrate an understanding of this as a basic qualification, said Prof Thio.
She said: "Surely a prerequisite for running for this office is to uphold the office and the province the Constitution has set for it, rather than to try and reconfigure the office in one's preferred image."
Some observers are also wary of setting the bar too high.
Assistant Professor Lee said there are no equivalent, stringent criteria for candidates standing in a general election.
"Yet, we trust the people to judge whether candidates possess the right qualifications to serve as MPs, and, possibly, to even hold key positions such as prime minister or finance minister," he said.
But the position of President is one that requires stringent criteria, said Mr Tong.
"It is serious business making sure that the Constitutional responsibilities are properly discharged," he added. "If the Elected Presidency fails as the guardian, Singapore fails. If we elect either a populist or a partisan President, what kind of an effective second key can he or she be?"