I would imagine the majority of the country is somewhere in the middle. Those who are in the extreme left or right tend to vote along party lines instead looking at an idea on it's on merit.
Awhile back I wrote a hub illustrating how political gridlock is the American way. Politics for many people is similar to sports. You support your team no matter what and you do everything to tear down the opposing "team"/party. People in the middle tend to dig deeper into an issue and come up with their own conclusions.