In game theory, there is a very famous "median voter theorem." It means that a candidate's campaign strategies will tend to lean toward the center in a two-sided election campaign. Whoever can stand firmly on the center can get more voter support and win.
In Taiwan, middle-of-the-road voters, or median voters, have become a crucial factor in winning single-seat elections. This group of people can swing the campaign results and determine the winner. They have no preference for any particular party. They are above ideology, highly independent and driven by campaign platforms and performance in office. They are dispassionate and do not blindly follow the crowd. They can think rationally and make discreet judgements.
When the voter bases of the blue and green camps are stable and even, these median voters will become the arbitrators that determine the outcome, thereby becoming the representatives of mainstream public opinion.
There is a considerable gap between median voters as interpreted by the media in Taiwan and the original meaning of the median-voter theorem. Usage of the median-voter concept is quite abstract and divergent. There is no strict, commonly accepted definition. When using the term, some members of the media frequently mix it up with "independent" or "undecided" voters.
Independent voters means voters who have no preference for any particular party. In Taiwan, such voters account for 30 percent to 40 percent of the electorate, according to opinion polls. Undecided voters are those who say, in opinion surveys, that they have not decided who to vote for.
Apparently, independent voters are not exactly the same as median voters. Independent voters account for a far larger proportion than median voters. In the media's description, median voters seem to account for only 10 percent to 20 percent of the electorate, numbering 1 million-plus votes. Independent voters merely means those who have no partisan preference. Many may be strongly candidate-oriented. But it does not necessarily follow that they are staunch supporters of a political party.
Nor are undecided voters necessarily the same as median voters. Voters who respond to telephone surveys by saying that they have not decided who to vote for may in fact be a highly complex combination of voters. Some of them may have long had a preference that they do not want to reveal. Some others may be floating voters who will support whichever side gains momentum in the end. Still others may be voters waiting to be mobilized by vote captains. They may remain undecided because they have not been given "walking fees" (fees to show up at rallies). Some may even be politically aloof or alienated. They may not even go out and vote at all.
After subtracting such voters, what remains is perhaps the highly independent median voters as described by the media. Can we categorize independent voters who have no partisan preferences and voters who say in telephone interviews they haven't decided who to support as median voters? We need to be careful with our interpretations.
For next year's presidential election, both the blue and green camps already have fairly stable voter bases. The key to victory will be winning over those who have not made up their minds. But what kind of strategies should the parties employ?