This is a very important "academic" debate and bears watching. Fiorina and Abramowitz are two of the major players in the debate. Of course, one must always return to James Davison Hunter’s book, The Culture Wars, which put the phrase and issue on the map.

My lay observation is that both are true. People believe they are polarized. By the clipped snapshot that is political opinion in America today they are polarized. But by historical standards we are not polarized. Political opinion is fairly well contained around what is the current center. But today’s current center is yesterday’s left.

Compare our politics to Europe, where you have everything from Communist to Fascist represented. (The European right differs from the American right so there isn’t really a large analogous small government right in most of Europe. Most of their right tends to be more nationalistic with a few exceptions. [Lega Nord, Vlaams Blok] But the point is the same.)

Diverse opinions do exist in America, but they don’t find political expression. This is partially/largely an artifact of the two party system. (And/or something about the American national character.)

I agree though. Interesting debate.

Isn’t the problem here, though, that there isn’t even one metric of partisanship or two but three, and what’s more, that there’s a distinct difference between (roughly) elites and masses? What I mean in regard to the former is that American politics generally breaks along three axes: social questions (things like abortion, homosexuality, etc.), economic questions (tax policy and the like), and foreign policy. And though people do tend to cluster in certain respects, they certainly don’t always do so. So it’s reasonable to be a pro-life high-tax isolationist and a pro-choice low-tax hawk. (You could complicate things even more by noting that few of those issues even really line up along a single continuum). As to the latter, as James Hunter never seems to tire of pointing out, the fact that the mass of people don’t sense that they radically disagree with one another doesn’t mean that there’s not a culture "war", because those sorts of cultural conflits are almost *always* led at the top. And while it’s no doubt unfashionable to say so, elite attitudes matter more than mass ones.

The very premise of this study is ridiculous, because it entails quantifying the souls of voters.

I read something some time ago saying that Americans are only divided into five real groups:

-Conservative (Socially and Economically conservative)
-Libertarian (Socially Liberal, Economically Conservative)
-Liberal (Socially and Economically liberal)
-Populist/Statist (Socially Conservative, Economically Liberal)
-Centrist

It also pointed out that the differences between these varying views of Americans and those of, say, Europeans, is that most of them each see the Constitution, but merely interpret it differently from one another. You’ll rarely find anyone calling for a new government (as they do through elections in parliamentary systems or revolutions in others). Most Americans have the same fundamental beliefs that make us American and respect the Constitution (and many the Declaration of Independence), but just think it means something different than their neighbor does.
So, I think post #3 in its assertion that something about our two-party system and the American character plays a large part in this.