Is Mr Lui Tuck Yew taking the rap for the rail breakdowns that do not seem to go away? Is the People's Action Party dropping him because it feels he may be a liability in the coming general election?
Looking at the timing of the Transport Minister's shock resignation, observers would be forgiven for such speculations.
The announcement of Mr Lui's decision came on Aug 11, just a month after Singapore's worst rail disruption. On July 7, trains ground to a halt for more than two hours on the most heavily used North-South and East-West lines, affecting more than 250,000 commuters in the evening peak.
Breakdown statistics had been less than rosy in the lead-up to that incident.Years after a public inquiry found that poor maintenance was largely responsible for the two crippling rail disruptions in December 2011, the number of major train incidents has not fallen.
Last year, there were 12 MRT delays that lasted more than 30 minutes - a four-year high.
In the first half of this year, there were already seven.
The LRT (Light Rail Transit) network is not faring any better. There have been eight major incidents so far this year, compared with five for the whole of last year and 10 in 2013.
In total, Singapore's rail network had 15 major disruptions in the January-June period. That works out to an average of 2.5 per month - up significantly from the 1.7 registered in 2011, which, until now, was the worst year for rail disruptions.
All that, despite the millions in tax dollars spent on a lengthy public inquiry that spelt out detailed steps to be taken to prevent the most disruptive kind of breakdowns.
If Mr Lui's resignation is his way of taking responsibility for the recurring rail incidents, it is honourable of him. Fairly or unfairly, the buck stops at the top.
That Mr Lui had been appointed second defence minister just three months earlier in May lends credence to talk that the July 7 breakdown was the last straw that broke the camel's back.
But from a national perspective, his resignation does not solve anything.
As Workers' Party chief Low Thia Khiang rightly pointed out when asked to comment on Mr Lui's decision, "resignation does not solve the problem... You have to stay on to solve the problem as a minister".
The Workers' Party had long campaigned for nationalising public transport, and Mr Low raised this obliquely when talking about Mr Lui's decision to quit.
He asked: "Was it because, philosophically, how they treat transport is not correct and not convincing to the Minister for Transport?"
Mr Lui himself put this to rest at a subsequent interview with The Straits Times.
He said the present operating model "can be improved but is fundamentally a sound one".
"All this talk about privatisation, nationalisation and whatever, frankly, I'm quite agnostic to whatever you term it," he said.
Private or public operator
Indeed, the debate over whether transport should be run by the private or public sector is an old one.
Those who favour privatisation tout superior efficiency as the top reason. This, however, has been challenged in recent years. Recent studies suggest that it matters little whether an infrastructure or service is in private or public hands.
Simply privatising a service does not necessarily make it better. History is replete with examples of privatisation failing miserably in the public transport arena.
British rail lines in the 1800s were built and run by private businesses. It led to unfettered competition, resulting in financially strapped companies which drew circuitous routes to avoid costly tunnelling.
It was the same story with Melbourne's rail lines and tramways in the early 20th century. Because of competition, there was no coordination, resulting in gaps between services.
For a more recent example, look to Britain's privatisation of its bus services in the Margaret Thatcher years. The outcome? Uncontrolled competition, cherry-picking of routes and diminished service standards. These eventually led to a steady decline in ridership (except in London), prompting calls for re-nationalisation.
Singapore, too, had its own taste of this. Before SBS Transit was formed in 1973, the island was served by several operators. It was an era of rickety, overcrowded buses and drivers racing one another to bus stops to pick up fares.
So, while privatisation in itself may seem like a good idea, there has been enough evidence to show that public transport in a laissez-faire environment rarely serves consumers well. A strong government hand is often necessary to ensure that service standards are met, and operators do not get into wasteful competitive practices or profiteer.
After decades of deregulation and privatisation starting from the 1970s, countries are beginning to realise that public sector involvement is crucial to the success of public transport.
Nationalisation is far from a cure-all, either. First, it does not guarantee efficiency. Going by the number of financial lapses flagged regularly by the auditor-general, having a state-run public transport system would not necessarily result in a better deal for commuters or taxpayers.
Second, nationalisation spooks investors. SMRT Corp and SBS Transit today, Singapore Airlines tomorrow?
Yet, state-run transport has worked well in some cases. The Taipei metro, owned and operated by Taipei Rapid Transit Corp, ranks consistently high in customer satisfaction and yet has been able to produce surpluses (profits).
Then, of course, we have the hybrid system which we are now moving towards: where the Government owns all fixed and operating assets, and contracts private companies to run services via competitive tenders.
This, too, has been criticised. London, which started bus contracting more than 30 years ago, has seen its bus subsidies climbing year on year.