[forum456]

1) Tharman and NKS are PAP supporters.
     Opposition supporters will never vote for them.

2) TKL is an opposition supporter.
    Most opposition supporters will vote for him.

3) Tharman and NKS are PAP supporters.
    NKS is also LKY supporter.
    PAP supporters will be split to support Tharman or NKS.

The above are facts.

Assuming ideal case.

TKL will get 40% opposition votes.
Tharman will get split votes of 30%.
NKS will get split votes of 30%.

TKL wins.