Our electoral system is fundamentally flawed. By having a system that inherently lends itself to a two-party system, you have the following scenarios, played out year-by-year:
A Democratic candidate has to appeal to the base, a typically far-left group of individuals. The Republican candidate must do the same for his base, and hold to the far right positions. Once they've been nominated by their respective bases, our ultra-liberal and uber-conservative candidates then rush to the left-of- or right-of-center positions, respectively, attempting to appeal to a relatively moderate nation. What happens then is that the candidates have to soften their messages with a wink and a nudge to their respective bases, assuring them that they'll always remember their roots.
What's peculiar about this election (not to disparage Obama any credit, because he ran a fabulous campaign) is that Obama didn't really soften his core message much - he ran on an essentially socialist economic platform. This message would never have resonated before with Americans, but it did this year because I truly believe that Obama benefited from such a passionate anti-Bush vote.
I fully expect to see a sharp turn back to two-party rule in Washington in the 2010 midterm elections, especially after a moderate America sees how liberal an unchecked Democratic power will be.