The shock People's Action Party defeat in Singapore's Punggol East by-election, won over the weekend by the opposition Workers Party candidate Lee Li Lian with 54.5 percent of the vote, seems a watershed in the island republic's politics.

Certainly it was a by-election, not a general one, so an opposition candidate could be expected to better than at the general election when the Workers Part candidate got only 43 percent of the vote. But a high turnout - 92 percent—indicates the degree of interest. The Workers Party was also helped by the fact that a second opposition candidate who got 4 percent of the vote in 2011 only received 0.5 percent this time. Also the PAP was smarting over adverse publicity relating to a controversy in which it abruptly pulled its electronic bookkeeping software out of a town council won last year by the opposition, after which the government red-flagged the council for keeping inadequate books.

However, there seems to be more to this result than simmering public resentment, which has also grown over such issues as immigration, housing prices, crowded transport and, for many, stagnant real household incomes despite years of trumpeted big gains in gross domestic product. They are issues that have been around for a while and were already reflected in the general election when the overall PAP vote declined from 66 percent to 60 percent.

The first indication of change may well be that although Lee Kwan Yew is still alive, at 89 he is no longer a figure on the stage, ready to warn of the Damoclean consequences for Singapore of PAP rule being challenged, or the consequences for constituencies should they dare to vote for an opposition candidate. While there has been no public comment on his health, his own silence is noteworthy.

His son, the prime minister Lee Hsien Loong, seems in turn to accept that he is not his father and cannot act in the same dictatorial way, hounding and bankrupting those who dared and succeeded in winning at the polls such as Joshua B. Jeyaretnam. On this occasion the younger Lee congratulated the winning opposition candidate, saying that he would "respect the choice of Punggol East voters." Congratulating Lee, he also praised People Action's Party losing candidate Koh Poh Koon for showing "character and courage."

Contrast that with the elder Lee, whose response to Jeyaretnam's win to become the first opposition politician in Singapore history was to abolish Jeyaretnam's constituency by redrawing the boundary lines so that the district no longer existed. He later said he would make Jeyaretnam "crawl on his bended knees, and beg for mercy," had him investigated and convicted on charges of cooking his party's books, bankrupted him and drove him from politics only to have him return, whereupon the government sued him for libel and bankrupted him again.

It matters too that the opposition is now beginning to have credibility and substance. Once it consisted of a few mavericks and who at best were personally respected, at worst seen as buffoons, who could never add up to an alternative government or make opposition votes more than a gesture of protest. But that is beginning to change as the opposition wins more seats and attracts better candidates - including, for instance, Lee Li Lian, a 34-year-old trainer at a financial institution, who put on a strong campaign in articulating the issues.

Opposition candidates are becoming more credible at a time when PAP ones are being shown up for the self-perpetuating elite they have become, entrenched not just in parliament and ministries but on the boards and management of the multitude of state-owned or linked companies.

Strength is self-reinforcing too because it gives the opposition more chance of winning the multiple seat Group Representation Constituencies (GRCs) where up to six seats can be filled by one party winning the plurality. This was introduced as a measure to thwart the opposition, which didn't have strong candidates to take on six seats at one time, but in 2011 the opposition managed to win one.

The system might even now turn in the opposition's favor. Single-member constituencies, of which Punggol East is one, provide only 12 out of 98 members of parliament. The success of the Workers Party in Punggol East following its triumph in the Al Juneid GRC in 2011 also means that a once very divided opposition is mostly now coalescing Meanwhile the system has tended to detach MPs from their supposed base and appear as mere appointees of a secretive and hierarchical PAP machine.

Of course the opposition still has lots of work to do but the momentum is there and even if the government addresses some specific voter grievances - and it is trying at least in the case of immigration - a younger generation seems much less in awe of the PAP and the Lee Kwan Yew system and may continue to demand change for the sake of it, and better distribution of the spoils of power.

In the Punggol East case, the PAP was a successful surgeon but with scant political experience or roots in his constituency. The elite character of the party, with its high-flying professionals and academics, has long been claimed to be one of its and Singapore's strengths. But it now looks a liability as people look to broaden the base of power as well as their ability to debate policy and question the assumptions of the PAP elite that they always know best.

As the shadow of Lee Kuan Yew's giant and often frightening reputation slowly fades, the aspects of Singapore for which he was responsible is just beginning to fade too. This is extremely awkward for his son, but Lee Hsien Loong, despite a past reputation for arrogance, may in his own maturity be recognizing that he can inherit the name but not the power and persona. Perhaps he has studied how Chiang Ching-kuo managed change after the death of his all-powerful father Chiang Kai-shek.