Today President Obama instructed the EPA to reconsider the Bush Administration's denial of California's request for a waiver of Clean Air Act preemption for the state's first-in-the-nation regulations limiting greenhouse gas emissions from new motor vehicles. This decision was expected, and is largely symbolic. Allowing California to regulate vehicular GHGs will have little effect on overall emissions, even if the dozen-or-so states that pledged to adopt the Golden State's standards as their own make good on their commitments. Yet the decision does signify that the Obama Administration will adopt a more aggressive posture on climate change than its predecessor. Perhaps it also indicates that the Obama Administration will have a greater interest in state environmental initiatives as well -- one can hope.

I have a brief comment on Obama's announcement at the NYT's new "Room for Debate" opinion blog. Other commenters include former EPA Administrator William K. Reilly and the Cato Institute's Jerry Taylor. I also blogged extensively about the Bush EPA's decision here and here.