IMO, Jim Manzi continues to own defenders of the preposterous cap and trade bill. His latest assessment of the state of play:

So let’s review the overall bidding, at least as I see it:

1. Everybody agrees that if Waxman-Markey becomes law, and it does not lead to a global, binding and enforced agreement to severely reduce global greenhouse gas emissions, then it makes U.S. taxpayers worse off economically.

2. I have presented an economic argument that even if such a global agreement were achieved it would accomplish in the best case a net increase in NPV of global consumption of 0.2%, and a practical argument that it would almost certainly reduce global economic welfare. These specific arguments remain undisputed.

3. Those who argue that Waxman-Markey would lead to a global agreement have provided no evidence that it would have this negotiating effect, and are presenting what is, at best, a pretty idiosyncratic negotiating premise that by giving away our leverage as one participant in a collective action problem we will somehow increase our ability to get others to sacrifice on our behalf.

The thing is, Jim's arguing from the basis of extremely generous assumptions.

Many of the people making a big deal about the bargaining value of this bill rarely (never?) use similar logic in similar circumstances. The idea is that coordinated international action toward carbon reduction is a global public good, and that the probability of effective coordination increases significantly if the U.S. acts unilaterally. HOW DOES THIS WORK? Standard statist-liberal reasoning about public goods is that they will not be provided unless there is a  coercive mechanism in place (e.g., a state) to solve the assurance problem. But there is no state with global jurisdiction. So am I to understand that folks making the argument about the crucial role for Waxman-Markey in solving the international collective action problem don't really believe the standard story about the need for coercion in assuring compliance? Because that would sure change a lot of debates about a lot of things! To put it another way: if you think that the probability is low that smaller-scale public goods can be provided through voluntary mechanisms without government, shouldn't you think the probability is even lower the larger the scope of the coordination problem?