In the 1991 General Election, Mr Chiam See Tong, then secretary-general of the Singapore Democratic Party (SDP), famously called for opposition parties to mount a "by-election effect strategy".
The concept was to contest only a minority of the seats, and so ensure that the People's Action Party (PAP) would form the Government on Nomination Day. This would in effect transform the general election into a by-election.
Then, people could vote for opposition parties without any worry that the government would fall into opposition hands. Indeed, the opposition won a historic high at that time, winning four seats and knocking the PAP's share of votes to 61 per cent.
Game theory - the mathematical model of strategic thinking - is essential to election strategy. The by-election effect strategy applies the game theory concept of pre-commitment. By deliberately contesting a minority of seats, the opposition pre-committed to not forming the government, ceding control of the Government to the PAP. This was SDP's response to the "freak election" result fear that mass voting for the opposition would inadvertently result in the PAP losing over 50 per cent of the seats, and losing power.
Instead, with the by-election effect strategy, Singaporean voters supporting opposition voices in Parliament could safely vote for opposition candidates without any worry of sending the opposition into power.
Another more recent aspect of opposition parties' strategy (whether intended or unintended) is not so obvious.
Let me call it the "national constituency" strategy. The Workers' Party (WP) applied it to great success in the 2011 General Election. Calling for a "First World Parliament", the WP concentrated its dream team of top talent (including secretary-general Low Thia Khiang and chairman Sylvia Lim) in Aljunied GRC. Applying the game theory concept of pre-commitment, the WP forced the voters of one constituency- Aljunied GRC- to vote as a national constituency. The only realistic way for Singapore to get a significant opposition voice in Parliament was for Aljunied GRC to vote for the WP. If the people of Aljunied voted against the WP, then they would wipe out the strongest of the opposition.
And, indeed, the WP overturned the PAP in Aljunied, unseating three ministers to win the group representation constituency and five seats in Parliament.
For the imminent polls widely expected to be held next month, WP has adapted the by-election strategy with a new twist. It will contest 28 seats in five GRCs (Aljunied, Marine Parade, East Coast, Jalan Besar and Nee Soon) and five single-member constituencies (Hougang, Punggol East, Fengshan, MacPherson and Sengkang West). By limiting itself to 28 seats, the WP is telling voters they are free to vote all 28 candidates into Parliament and still assure the PAP of a two-thirds parliamentary majority. There are 89 seats in Parliament for the next election.
The WP is thus applying the pre-commitment strategy in a different way. But by doing so, it will not be able to play the national constituency strategy so effectively. It is now the incumbent in one GRC (Aljunied) and two SMCs (Hougang and Punggol East). It will field an array of new talent, including a university professor and an Oxford-educated government official turned consultant, and contest 28 seats.
The risk for the WP is that the PAP adopts a new strategy of local elections in every constituency. The PAP could call for people to vote local (elect people who can effectively manage their town council) and let other constituencies send the opposition to Parliament.
Indeed, PAP's organising secretary Ng Eng Hen broke with tradition by presenting the party's Bishan-Toa Payoh GRC slate at a heartland coffee shop rather than the PAP headquarters, a move that commentators think suggests the PAP's strategy is to fight at the local level in every ward. This view is buttressed by the way the PAP is announcing its candidates within the constituencies they are standing in, and by the way it is rapidly announcing its constituency plans to voters.
Will the WP's strategy of ceding parliamentary majority to the PAP assure opposition supporters that they can safely vote for WP candidates in the 28 constituencies, without fear of diluting the PAP's ability to govern? Or will the PAP's strategy of fighting locally, and urging voters to compare its slate with that of the WP's in each constituency, win over voters?
With tough fights expected between the PAP and WP in the wards contested, even subtle changes in strategy can change the outcome on Polling Day.
• Ivan Png is Distinguished Professor in the Department of Strategy & Policy at the National University of Singapore Business School.