I understand your inclination towards doing away with a two-party system, but as long as we elect exactly one president, a two-party system does tend towards mo

I understand your inclination towards doing away with a two-party system, but as long as we elect exactly one president, a two-party system does tend towards moderate policy. My intuition on this goes as follows: Imagine one single spectrum of policy, that goes from "Left" to "Right" for example. Assume voters exist somewhere on this spectrum, and will vote for the candidate whose policy is nearest to theirs on the spectrum. Then so long as there are exactly two viable candidates then they both have no incentive to deviate from the median voter. Each candidate picks up one whole side of the spectrum, and the only thing that can happen as a candidate makes their policy more extreme is that the median voters begin to see the other candidate as closer. Of course, the actual US election system is far more complex. Very extreme voters do in fact "throw their vote away" if both candidates appear far from their policy. There are a lot more issues than just one, so a single spectrum of policy is oversimplified. Many voters vote on individual issues, which are often black and white (e.g. pro-life/choice, for/against gay marriage). You could probably argue that candidates actual policies have very little to do with their stated policies, or that voters are significantly more swayed by advertising dollars than policy. All of these are real concerns, but I think the basic point stands: a two-party system encourages both candidates to situate themselves at more or less the median of the American electorate, which I consider a desirable outcome.