it's also true that polarization isn't ideologically neutral. As Obama recognizes, it favors conservatives--or, rather, favors a certain cynical, nihilistic strain of conservatism that wants not only to limit the size of government, but (for reasons almost passing understanding) to impair its capacity for performing even governmental functions broadly recognized as necessary. In a political system that is (appropriately) biased toward the status quo, polarization--which makes it all but impossible to develop the consensus required for any important policy change--plays into the hands of those who rejoice at the thought of a paralyzed, ineffective federal government.This actually fits in quite well with my comparison of this year's primary with the War on Terror. Just as the administration believes that we need to fight the terrorists by becoming more like the terrorists, so some Democrats believe we need to fight Republicans by becoming more like Republicans. They champion Hillary as somebody who can fight the Republicans, who can do bare-knuckle scrapping. But the terrorists aren't troubled when we take away civil liberties and torture people--that can fit in quite well with their plans. And throwing rhetorical bombs at Republicans doesn't bother them, either--they live for the opportunity to pull out the macho bluster. And they don't mind that polarization keeps us from getting anything done.
Note that in the post, Obama says, "When I say I want to change politics, it's precisely because I want to make sure people have health care." That's the kind of person I want in office, somebody who realizes the goal of politics is not to score rhetorical points against the other side.
