Singapore, known for its political stability, has been rocked by a string of rare political scandals.

Last week, a senior minister was arrested in a graft probe, the first in four decades to be implicated in such an investigation.

And on Monday, two lawmakers – one of them once tipped as a potential prime minister – resigned after it was revealed they were in an extramarital affair.

It has shocked residents of the city-state, which prides itself on its reputation for clean governance and has the highest paid leaders in the world.

Analysts say the unfolding scandals could dent support for the ruling People’s Action Party (PAP), which has been in power since 1959 and holds a large majority in parliament.

They also say it casts doubt over when Prime Minister Lee Hsien Loong can hand over the reins of leadership.

On Monday, Speaker of Parliament Tan Chuan-jin, 54, and fellow lawmaker Cheng Li Hui, 47, resigned from the party and the legislature over their “inappropriate relationship”. Mr Tan is married, while Ms Cheng is single.

More questions on transparency arose last week, when Singapore’s anti-graft watchdog arrested Transport Minister S Iswaran and billionaire hotelier Ong Beng Seng. The two men played key roles in bringing the Grand Prix to Singapore in 2008.

Singaporeans were told last Wednesday that Mr Iswaran had been asked to take leave from his ministerial duties amid a probe.

Deputy prime minister Lawrence Wong has told local media the corruption probe would be “full, thorough and independent”, and that nothing will be swept under the carpet.

But authorities only announced the arrests three days after they actually took place. Both men have not been charged and are currently out on bail.

The arrests came on the heels of allegations that two other senior ministers had rented colonial-era bungalows in a high-end neighbourhood at below-market rates.

While an anti-graft review cleared the two men, K Shanmugam and Vivian Balakrishnan, of wrongdoing, the matter sparked a heated debate on inequality in Singapore and political optics.

The unusual series of events has bought out the inevitable memes. “The writers of this season of Singapore have really outdone themselves,” wrote the creators behind Instagram page yeolo.sg on Monday.

A separate post, featuring actresses on the set of the Barbie movie crowding around a laptop, read: “When me and the girlies are suddenly interested in sg politics.”

Another Instagram user wryly compared the current political situation to spilling tea, or sharing gossip.

But beyond the jokes lie serious questions about the future of the PAP and how long it can hold on to Singaporeans’ trust.

It has weathered similar scandals in the recent past – in the last decade a previous parliamentary Speaker and a backbencher stepped down because of extramarital affairs. But the close timing of the scandals and corruption probe has heightened voters’ scrutiny.

The PAP has long prided itself on demanding high moral standards of its lawmakers, and its ability to keep its house in order. One of its founding members once compared joining the PAP to joining the priesthood.

Mr Lee this week defended his party’s handling of the recent scandals, saying it demonstrated “how the system has to function”.

“Sometimes things cluster up, but we make sure we put them right,” he said, adding that “high standards of propriety and personal conduct… are the fundamental reasons Singaporeans trust and respect the PAP”.

But other observers contend these controversies call into question Singapore’s – and in particular, the PAP’s – claims to exceptional governance.

“I think the biggest questions surround restraints on authority, oversight, transparency, the impartiality of parliamentary process as well as the PAP’s claim that it is a sufficient check on itself,” said Singapore-based political scientist Ian Chong.

He noted that the PAP has rejected political practices common in other developed jurisdictions, such as public disclosure of income and assets by political office holders, senior civil servants and their immediate family members.

There are no robust mechanisms for holding powerful people to account, added Michael Barr, an Australia-based international relations professor who has written several books on Singapore politics.

“You just have to trust them. That is why this is such a dangerous and novel set of developments for the government. They are trashing their repositories of public trust,” he said.

Singapore is ranked the fifth-least corrupt country in Transparency International’s latest Corruption Perceptions Index. Over the years, the government has justified seven-figure ministerial pay checks as a way to repress corrupt activity.

But Dr Barr pointed out: “Without extraordinary levels of public trust, the government must rely on one of two things to win elections: either repression and other measures that subvert democracy, or a high level of performance-based legitimacy. Their record in recent years is such that we can forget about performance legitimacy.”

The recent events also cast doubt on when Mr Lee would step down.

The 71-year old, who has been prime minister since 2004, has often spoken of his wish to retire. A successor has already been designated: Lawrence Wong, who is also finance minister.

But on Monday, Mr Lee said he has no plans to call for an immediate general election. The next polls are due by November 2025.

The fact that Mr Wong has not been more active and visible in addressing the recent scandals also raises questions about him and his peers’ readiness to take over as the city-state’s leaders, noted Dr Chong.