George Monbiot brings up some good points in We've been suckered again by the U.S.
One hears repeatedly that campaign finance reform has for a long time been identified as the number one goal by people serious about making change for the better in the U.S. But how can this become a reality? Barack Obama, for example, may have remarkable qualities, but major change-maker may not be one of them, and (most unfortunately) he looks to me like a prime candidate for assassination.
Even with reform, almost any greenhouse gas cap and trade is likely to be vulnerable to abuses. Other systems can be gamed too, of course. The point is to learn from those mistakes, and there is some evidence of this happening with CDM and EUETS.
Also, it's not only the U.S. that plays fast and loose. See UK's official CO2 figures an illusion.