The spoiler effect may well have been the cause of Dr. Tony Tan's victory in the recent 2011 Singapore Presidential Election. I do not wish to comment much on this, apart from making the point that First-Past-The-Post voting systems have several disadvantages as compared to other more complex preferential voting schemes.
What I do find interesting is this: It is known that there are very high entry barriers to running in the Singapore Presidential Elections; these entry barriers manifest themselves first in the high standards required to obtain a Certificate of Eligibility, and second in the hefty election deposit. High entry barriers act to deter and perhaps to impede alternative candidates from participating in the elections. Yet from this election it appears that allowing more candidates to participate actually improves the chances of victory for the establishment candidate.
Lowering the entry barriers allows more candidates to participate in the elections, and increases the fragmentation and splitting of votes (though tactical voting will limit the effect, but I despise the very idea of tactical voting). However, at the risk of adopting a binary view of the political system, I speculate that the establishment may be assumed to be sufficiently disciplined to put forth only one candidate, and hence is less susceptible to split vote effects.
Therefore, I wonder if the governing party would be more advantaged if there were actually no entry barriers erected in place.