I think that most Americans can be found in the middle of the two extremes (far-left/far-right) but our political system is set up to reward those who pander to the extremes (Gerrymandering + closed primaries in most states), so we wind up with this system that swings back and forth between the two, rarely settling in the middle where most of the electorate lies.
I hate that left/right division - the reason most people come down "in the middle" is that there's no way to really identify an individual on that spectrum that is consistent - most people have opinions on both sides - sometimes very extremely. So -- for example -- you may be for legalisation of all drugs always, and think you're a libertarian, but hate banks and want them strictly regulated. I know this person - he doesn't see a conflict. Or, you could be hard-line anti-abortion and also pro-union - where the fuck does that put you? (other than old-school Irish Catholic - i.e. deeply in the Democratic party).