Preferrential voting would solve that problem, Doug. It works surprisingly well in the places that use it. It's also known as "Instant Runoff"

For example, if you wanted to vote for Nader, but didn't want to help Bush, you could vote (in this hypothetical election):

1. Nader 2. Gore 3. Bush 4. Perot 5. Buchanan

When Buchanan comes in as the candidate with the least votes, those ballots with him listed as #1 get bumped to their #2 candidate. Meanwhile, everyone else continues to support their #1 candidate. This process continues until one of the candidates has a majority vote. If you absolutely don't want to vote for someone, you don't have to -- you can rank as many or as few candidates as you want. You can only rank one if you want.

It's more accurate than plurality elections and doesn't require the voter to go back to vote again like runoff voting. It's also cheaper than runoff voting, and has been shown to improve voter turnout where it's used. It's gaining popularity in local elections, particularly in places where there are viable 3rd party candidates. It removes "spoiler" votes (and the inevitable fakes candidates),

It'll be interesting to see what happens in San Francisco next year when they adopt it. There are a lot of nearby cities considering it, and SF is kind of a test case. If it works well in SF, it could cause a cascade effect here and then probably

The Utah Republican Party used it to do their primary election for House Reps. Even in places with strong 2-party systems, it could improve the primary process by suporting candidates who are most in line with the majority's opinions.