Jonathan Chait makes the case for continued optimism on health-care reform. I basically agree: I view American politics through a structural lens, and almost all of the relevant forces are pushing Democrats toward completing a bill. But in the interest of full disclosure, here’s what worries me:

(1) The collective action problem: Even though passing a bill leaves all Democrats better off, voting for a bill leaves some Democrats worse off. There are members of the Democratic Party who desperately need a bill to pass, but also feel that they need to be able to vote against that bill. These people are probably going to lose their elections one way or the other, and virtually none of them seem willing to simply admit that and do an enormous amount of good for the American people before Democrats inevitably and predictably lose their unsustainably large majority.

(2) Individuals are not rational: Which means predicting what they’ll do based on the “this makes overwhelming sense” criteria is not a foolproof strategy.

(3) Legislators do not understand health-care reform very well: A lot of these congressmen don’t know much about the bill, or the health-care system, or the interaction between the two. Some on the left think the absence of the House’s public option renders reform meaningless, even though the public option in the House’s bill would have made very little difference either to people or to costs. Some on the right think this bill will increase costs despite scores of evidence showing otherwise, and despite the fact that the delivery-system reforms and the construction of a competitive insurance market represent the most ambitious cost control effort that’s ever been passed into law.

(4) Inaction is easy: If health-care reform was guaranteed a vote, I’d be pretty confident in its passage. But if the House and Senate simply do nothing, the legislation dies. That means there’s a path of least resistance — which is not the same as a path of least consequence — that Democrats could end up walking, even as they continue to promise that they’re committed to voting on health-care reform sometime soon.

(5) The House and the Senate hate each other: And for health-care reform to pass, they’re going to have to trust each other, at least a little bit.

By Ezra Klein | February 23, 2010; 12:34 PM ET