>>4
The current balloting system of most elections in the U.S. (barring some local ones) ensures that if you simply vote for the candidate who most accurately represents your views, instead of carefully selecting a compromise candidate who is likely to accrue a significant percentage of the vote, you may have easily thrown half a vote to a popular candidate who diametrically opposes your political views, with your own vote accomplishing nothing.
Since most people are stupid, and prefer those candidates which lull them with promises and ideas rather than boring political discourse about issues that matter, those are the most likely compromise candidates. Thus, independent-minded voters who do not choose a candidate based on ideology or popular sentiment- Nader supporters in 2000, for instance- are actively punished and made to feel like betrayers of their political constituency.