So who was driving the absolutist view in Congress over the past few months? If it was the no-compromise wing of the tea party, that's less than 10% of the country. So riddle me this: how did we manage to let 10% of the country bring us to the brink of disaster? It is a remarkable thing.I think the answer is to see Republican issue positions as a function of elite preferences, not mass preferences. In particular, it's all about the domination of the GOP by the anti-taxers. Given that, any electoral victory by the Republicans will produce policies that reflect that domination.
Of course, the next question is why a minority preference within the GOP has won out. That's a harder question to answer. It seems to have something to do with the influence of those with intense preferences; something to do with interest-group politics within the party; something to do with the surface appeal of a simple message (it's not surprising to me that politicians are easily persuaded that no one wants higher taxes, regardless of what the polls show); and something to do with the lucrative market for certain conservative products, and the mechanisms in which exploiting that market affect actual Republican party policy preferences.
Some of these processes are completely normal within American politics, some of them are more recent but apply to both parties, and some of them -- that last one -- appears to apply to the GOP alone. And I don't think we (and in this case, the "we" means academic party scholars) have a good handle on the whole thing. We know that all of those are contributing factors, but couldn't get much beyond that.
I'll add one thing: if we restrict public opinion to real preferences, and not just whatever people are willing to say when a pollster bothers them on the phone, then it's probably the case that minorities, usually small minorities, always win -- because there are no real majorities on most issues. Or, to put it another way, the majority of Americans generally either don't know or don't care (or at least don't care very much) about most public policy issues. Sure, on the big questions, people certainly have a strong preference for a thriving economy to the one we have, and there are other big-picture things where preferences are probably real and meaningful -- and many Americans have a small set of issues on which they do have passionate views -- but most people just tune it all out most of the time. So to some extent the question is why this particular minority wins in this particular case, not how a small minority could win at all.