I just about entirely disagree with Matt Yglesias's belief that parliamentary systems produce progress-by-alteration, in which parties embrace moderation in order to please the voters, knowing that they cannot take extreme positions because they'll actually have to implement them if they win. Well, I should say -- I think that's just as likely to happen in the US system of separated institutions sharing powers; after all, for over two centuries, including during earlier times of polarization, complaints that there was little difference between the parties were common. I really don't think that the current pathologies of the GOP have anything to do with Madisonian structures -- nor do I read the history or theory of governance in Westminster systems as generously as Ygesias does. I mean, he says that in "bipartisan by alteration...we would have no fiscal consolidation in 2011 or 2012, since none is necessary," which to my mind sort of insanely overlooks what the Brits are doing right now.
All that said -- he's absolutely correct about one thing: it's true, and unfortunate, that the US political culture places a premium on grand bargains, and in general is dismissive of partisan solutions.
We're in a very partisan age, which I think everyone recognizes, but there's virtually nothing in the political culture that celebrates or affirms partisanship. Nor do the parties themselves even develop strong symbols and rituals of partisanship; poke an activist, and nine out of ten times she'll tell you that she's not "really" a Democrat (or Republican); she believes in the issues or the ideology, but not the party. Now, from the outside such protestations seem paper-thin; most activists behave as if they were strong partisans, and (in my view) ideology appears to follow party, not the other way around. But it doesn't feel that way to people within the system.
In that sense, the most interesting thing about the Tea Party stuff was that it succeeded -- wildly, I'd say -- in precisely those symbolic and ritual ways that Democrats and Republicans fail.
At any rate...I think it's too bad that so many Washingtonians believe that grand bargains are a good thing, that they are inherently better than partisan solutions, and that indeed partisan solutions to big problems are impossible.