Buzbee on floors and ceilings

I appreciate Michael's link to Prof. Buzbee's recent paper on pre-emption, and regulatory floors and ceilings.  As Michael says, Prof. Buzbee is an expert in the relevant areas, and so his work would be quite useful to anyone trying to decide whether the the Bush Administration's federal-ceiling efforts comply with the relevant law or are good policy.  And it would, it seems to me, be a good thing -- as a general matter, anyway -- if federal regulations in a wide range of areas were more consistent with this observation of Prof. Buzbee's:

Unitary federal choice preemption is an institutional arrangement that threatens to produce poorly tailored regulation and public choice distortions of the political process, whether it is before the legislature or a federal agency. Floor preemption, in contrast, constitutes a partial displacement of state choice in setting a minimum level of protection, but leaves room for other actors and additional regulatory action. Floors anticipate and benefit from the institutional diversity they permit.

That said, it does not appear -- from my quick first glance, anyway -- that Prof. Buzbee is arguing that cap-and-trade regimes are "scheme[s]" that would "let some plants evade cleaning up their pollution" or that to support such regimes amounts to promoting the "the interests of the economically powerful rather than protecting the public's health".  So, Michael . . . what about cap-and-trade regimes as a way of controlling and reducing pollution?