SINGAPORE - While Prime Minister Lee Hsien Loong has said that his successor has not yet been chosen, his actions over the last few weeks suggest that, at the very least, the field is starting to narrow.
First, there was the appointment of Education Minister Heng Swee Keat - already two years into helming his ministry, and fresh from organising the Our Singapore Conversation - as the chair of a yet another key national committee, one to commemorate Singapore's 50th year of independence.
Then on Wednesday, Acting Minister for Social and Family Development Chan Chun Sing was promoted to full minister and made Second Minister for Defence.
The class of 2011 is meant to form the nucleus of the fourth-generation leadership that is slated to take over in 2020 (depending on a People's Action Party win, of course).
With these recent moves, it would seem clearer who the front runners to be the next PM are.
In Singapore politics, history would suggest that speed matters.
Those who make it to the very highest echelons of political leadership seem to have a few things in common: They are identified very early on, given a lot to do, and rarely look back.
Out of nearly 40 Cabinet ministers since the 1970s, those who rose to the very pinnacle, first became full ministers the fastest among their cohorts and typically in under three years.
To be exact, the two prime ministers after Mr Lee Kuan Yew had been elected for a little over two years before they were made full ministers.
In the case of President and former Deputy Prime Minister Tony Tan Keng Yam, who was identified as being of PM calibre, the length of time was just one year and three months.
If history is to be a gauge, Mr Heng and Mr Chan - who will become full minister next month after two years and four months since being elected - are being set apart from the rest of their cohort.
The others with them include Mr Tan Chuan-Jin and Mr Lawrence Wong, who were both made Ministers of State in 2011, then promoted to Acting Minister last year in their manpower and culture, community and youth ministries respectively.
PM Lee said the lack of a promotion for them this time round does not reflect that they have not performed and he said that they "may be a step behind".
So while the Prime Minister says the choice of his successor will be left to the younger ministers to make, his actions suggest he is helping steer the sorting out along.
Yet, caution is required when trying to read the tea leaves based on these historical precedents.
The numbers paint a fascinating picture but past patterns are not necessarily predictive of the future.
Each generation of leadership comes in under largely different circumstances and contexts.
Some will, for instance, argue that the quick elevation of Mr Chan and Mr Heng has also been out of necessity. And here several other observations need to be made about the leaders of the fourth generation.
One, that our next PM could likely be the oldest ever. Two, he and his team will have the least electoral battle experience. And three, they will have a much smaller window of time for teething.
How did the PAP's leadership renewal reach this stage?
It can be traced back to the 2001 cohort, which yielded the "super seven", one of the largest infusion of ministers in history, all of whom were also already in their 40s.
That core of that class - headed by Deputy Prime Minister Tharman Shanmugaratnam who entered politics at the age of 44 and is now 56 - is deemed by observers as a little too old to be in the running as PM Lee's successor. In any case, Mr Tharman has also ruled himself out.
Among the seven, of whom only four are still in Cabinet, Minister for the Environment and Water Resources Vivian Balakrishnan, at 40 then, was the youngest and the only one born in the 1960s.
Health Minister Gan Kim Yong, two years older than Dr Balakrishnan, is also part of that cohort though not of the original seven.
The crop from the 2006 polls has yielded only two Cabinet ministers for the PAP since - Minister for Transport Lui Tuck Yew and Minister in the Prime Minister's Office Grace Fu. Mr Lui was promoted in 2011, and Ms Fu last year.
The ages of the class of 2001, and the small crop from 2006, put immense pressure on the 2011 cohort to produce the bulk of the fourth-generation core going forward with only seven years until the unofficial deadline.
That will affect the teething time and electoral experiences of the current class.
Mr Heng was already 50 when he entered politics, making him just the fourth man to enter politics at age 50 or older.
Of the three who did, going back to the 1970s, all were made full minister immediately. But two of them - Mr Teh Cheang Wan and Mr Howe Yoon Choong - stepped down after just two terms. The third, Dr Richard Hu, was Finance Minister for four terms.
If Mr Heng becomes the next PM in 2020, he will be 59. Mr Chan will be 51. Moreover, they will have contested in only three general elections come 2020.
Compare this situation to previous leadership successions.
The core of the second generation of leaders were all in their 30s when they entered politics.
Mr Goh Chok Tong was 35, Dr Tony Tan Keng Yam and Mr S. Dhanabalan were 39, and Mr Lim Chee Onn was just 33.
They contested four general elections before Mr Goh took over as Prime Minister in 1990 at the age of 49.
Similarly, among the third generation, PM Lee Hsien Loong entered politics at the age of 32, former DPM Wong Kan Seng at 38, former Foreign Affairs Minister George Yeo at 34, and DPM Teo Chee Hean at 37.
PM Lee fought five electoral battles before taking over the helm in 2004, at the age of 52.
Even though these men were given heavy responsibilities quickly, there was time to test them out, let them gain experience, and weed out the weak.
These differences from the current batch's situation bring home the great sense of urgency for leadership renewal from the PM's perspective.
And if the timing of Mr Chan's and Mr Heng's ascent seems to point to bigger things in the future, what of their portfolios?
That Mr Heng has been entrusted to lead two important committees is telling, but some observers had questioned Mr Chan's position when he was put in charge of a smaller ministry.
In the past, the most promising young ministers were typically blooded in the ministries of trade and industry, as well as education - key pillars of Singapore. Mr Chan's posting to the Social and Family Development Ministry (MSF) is therefore conspicuous.
Perhaps it is an indication from the PM that the next generation's leaders have to prove their understanding and empathy with the social needs of Singaporeans, and not just their economic goals.
It is also perhaps telling that the broadened social safety nets under the "new way forward" announced at the National Day Rally will require key contributions from the MSF.
Indeed, from handling ageing population and fertility issues, to tackling income inequality and stubbornly low wages, the social needs of Singaporeans are increasingly many and varied.
With the times a-changing, the rapid ascension of Mr Heng and Mr Chan is a nod to their qualities.
But equally, it is a decision borne out of necessity, with both eyes firmly looking at the window for which the next leaders have to get ready, and seeing it shrinking with each passing day.
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