Monday, June 11, 2007

Plurality Voting: Has It Outlived Its Usefulness?

The current voting system we use is called plurality voting. It's the most widely used system in the world at the present time. Its main advantage is simplicity: it doesn't take a rocket scientist to figure out how it works. And it works fine most of the time, IF there are only two candidates. Unfortunately, that's the exception rather than the rule in recent Philippine presidential elections. When there are three candidates or more, the limitations of plurality voting become readily apparent.

In a two-way contest, one candidate would always get the majority of the votes. He or she comes into office with an unquestioned mandate: it can't be disputed that more than half the citizens who voted preferred this particular candidate for this position. When you add another candidate to the mix, however, things can get sticky. Imagine an election in which FPJ, GMA and Raul Roco all ran for president. Suppose FPJ got 45%, GMA got 35%, and Roco got 20%. Under the rules of plurality voting, FPJ would be proclaimed president even if he didn't get a majority. A plurality (45% in this case) is all that's required. Consider what this means: 45% prefer FPJ as president, but 55% would prefer somebody else first. Clearly, this mandate won't be as strong as one accompanied by a majority.

Consider further if, hypothetically, 90% of those who voted Roco had GMA as their second choice while 10% had FPJ. Thus, if Roco were not to run, his votes would be split between FPJ and GMA, with most going to the latter. In a two-way race, GMA would have gotten 53% [35% + (20% x 90%)] while FPJ would've gotten 47% [45% + (20% x 10%)]. Given a simple choice between FPJ and GMA, the voters would choose GMA, but the addition of a third candidate to the race (Roco) sufficiently alters the dynamic to allow an FPJ victory. The result is an outcome unacceptable to 53% of the electorate, a paradoxical result.

In a real world example you might be familiar with, the 2000 U.S. presidential elections, there was a third candidate, Ralph Nader, appealing mostly to Democrats who would otherwise have gone for Al Gore. Nader was able to garner enough Democratic votes that Gore lost narrowly to G. W. Bush. If Nader hadn't run, Gore would easly have won the presidency, and with a majority at that.

Closer to home, the 1998 presidential elections saw de Venecia, Roco, Osmena, Lim, de Villa, Defensor-Santiago and Erap, among others, contesting the presidency. Erap won with 39.6% of the vote. De Venecia got 15.9%; none of the others got more than 14%. Conventional wisdom at the time had it that the same demographic was being courted by all the major candidates except Erap (who relied on his "masa") and Osmena (who represented the Cebuano vote). Had de Venecia been able to count on the votes that went instead to Roco (13.6%), Lim (8.7%), de Villa (4.8%), and Defensor-Santiago (2.9%), Erap might never have become president. As it was, Estrada was sworn in with 60.4% of the electorate preferring someone else. More importantly, perhaps as much as 45.9% (combined total of de Venecia, Roco, Lim, de Villa and Defensor-Santiago votes) thought him unacceptable for the post. Might this have contributed to his downfall three years later? Possibly.

Perhaps plurality voting is not the ideal system to use in a polity such as ours. Numerous interests as well as personal ambitions conspire to erode the influence of parties, and restoring the de facto two-party system of the pre-Marcos years remains a pipe dream. Indeed, special interest groups are quite happy with the multi-party circus we have now, and some quarters are even calling for a partyless democracy. Without political duopolies to focus diverse contending interests into two-way races, we will continue to have multiple candidacies for each election, and we will continue to run the risk of our plurality voting system producing paradoxical results.

Next, we look at run-off voting...

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