There are only three changes in Prime Minister Lee Hsien Loong's upcoming Cabinet reshuffle to take effect on May 1, 2019.

1) Finance Minister Heng Swee Keat will be promoted to Deputy Prime Minister (DPM). He will be appointed Acting PM in PM Lee's absence.

2) DPM Teo Chee Hean will be appointed as Senior Minister and continue as Coordinating Minister for National Security.

3) DPM Tharman Shanmugaratnam will be appointed as SM and re-designated as Coordinating Minister for Social Policies.

On the surface, it appears to be a low-key cabinet reshuffle with very minimal changes to ministerial portfolios and office-holder promotions.

But this cabinet reshuffle may well have more longer term implications compared to previous Cabinet reshuffles by PM Lee.

1. A Cabinet with only one DPM allows the next PM more say in choosing his DPMs

PM Lee has broken with the two DPMs tradition.

Singapore has had two DPMs supporting the PM in most of the later years of the late Lee Kuan Yew's premiership in 1980.

This was when the late S Rajaratnam was appointed alongside DPM Goh Keng Swee as the second DPM.

PM Lee however was also the only DPM from 1993 to 1995.

What is also significant is this will be PM Lee's first Cabinet with one DPM, come May 1, 2019.

The sole promotion of Heng by PM Lee indicates clearly to all that Heng is the front-runner both in the ruling party and the government to be Singapore's fourth PM.

PM's promotion of Heng has helped Heng put some healthy distance from Chan Chun Sing.

The joint press conference by Heng and Chan in People's Action Party (PAP) colours in November 2018 may have given some the impression that Heng and Chan are co-leaders in the 4G leadership team.

This has led to Emeritus Senior Minister Goh Chok Tong making the following remark in a CNA interview:

"That’s (the choices made by the 4G leaders to choose Heng and Chan as leaders) not quite so, you see.

The ministers and office holders decided on who should be leading the team. So Mr Heng Swee Keat was chosen to be the leader, and Mr Heng, in my view, quite wisely chose Chan Chun Sing to complement himself."

With the promotion, Heng's position as the next PM is clear.

More importantly, PM Lee has provided Heng with a clean slate to choose his future deputies.

For instance, Heng could use either of the three permutations to select his deputies in future.

He could i) select two 4G leaders as his deputies; ii) choose one 3G and one 4G leader as his deputies; or iii) opt for two 3G leaders as his deputies.

PM Lee went for option iii first, choosing two 2G leaders (Tony Tan and S Jayakumar) as his deputies, before going for a senior-younger DPM combination (Jayakumar-Wong Kan Seng, Wong-Teo)

2. A Cabinet with two SMs allows more 3G leaders to support the 4G leaders in future

PM Lee has revisited a political arrangement -- having two SMs in Cabinet -- that was discontinued after GE 2011.

ESM Goh and Jayakumar served as SMs from April 2009 to May 2011.

Previously, there was only one SM per Cabinet.

While the late S Rajaratnam was the SM for three years in the 1980s, the SM role was truly institutionalised with LKY's appointment.

LKY became the SM when he stepped down as PM in 1990.

The system of having a former PM as an SM lasted for nearly 21 years, and spanned across the two premierships post-LKY.

With two former PMs becoming SMs after they stepped down, PM Lee is likely to follow the same footsteps as his predecessors.

Hence, PM Lee is helping Heng to reduce the surprise element if Heng were to have PM Lee and either DPM Teo or DPM Tharman as the two SMs.

At 62, DPM Tharman will be the youngest ever minister to be SM.

3. PM Lee priming Heng to have more say in economic policies?

In a low-key Cabinet reshuffle, what has caught our eye is what was left unsaid in the PMO statement.

The PMO noted that Tharman’s role as Coordinating Minister of Economic and Social Policies will be adjusted to remove the term “economic”, and it included an additional sentence that says he will continue to advise PM Lee on economic policies.

If Tharman's role as the coordinating minister was to remain the same, there will be no need for the redesignation, like DPM Teo's role as the coordinating minister for National Security.

What could the redesignation mean?

It could mean that Heng, as Finance Minister, is likely to play a bigger role in economic policies.

Or it could well mean that two 4G leaders -- Heng and the Trade and Industry Minister Chan Chun Sing -- will co-lead economic policies.

Top photo via Heng Swee Keat Facebook