How will the EPA tackle greenhouse gas emissions?

The New York Times' Room for Debate Section has some good (and more accurate than last time) commentary on possible directions the Obama administration can head in regulating GHGs. Most commentators agree that, generally, there are two solutions: 1) regulate GHGs under the Clean Air Act, or 2) work with Congress to create a new law.
The first option is attractive because the framework already exists. The detractors point out however, and I agree, that the CCA was developed to deal with smog - particulates floating in the air in urban areas. GHGs create different effects and come from different sources. A greater expanse of the economy would be affected and regulated, as John D. Graham points out.
Thus, the second option makes some sense, though it make take years to formulate. The law could be crafted so the EPA would have the proper tools to regulate GHG emissions in innovative ways.
There's an option which was not mentioned, however. Perhaps while the U.S. formulates it's own policy, the Obama administration can release the states from federalism issues and allow them to create pilot programs. They are the nation's laboratory of laws, after all (as pointed out in other posts). In fact, thanks to George W. Bush's inability to pass meaningful mercury federal regulation, over 20 states have begun to tackle that problem themselves, though in the shadow of threatened federalism litigation. The states might develop more innovative ideas than the federal government could, while at the same time expose any future roadblocks.
Finally, Robert Hahn and Peter Passell bring up the inherent global problem with any program to regulate GHG emissions. Even if the U.S. does formulate a coherent policy and regulatory program to reduce our own emissions, unless growing industrial nations such as China and India do the same, our effort is eviscerated on a global scale. They are correct that whatever our effort is, we have to create incentives to transfer clean technology to those nations. But I'd like to emphasis that we still have a moral obligation, as a world leader, to reduce our disproportionately large contribution to this problem. We must accept our role as that leader, to go when others might not.