The regulations at issue were EPA's cap-and-trade rules for interstate air pollution, a problem that EPA has been trying, without much success, to deal with virtually since its inception (in 1970). The case at bar was EME Homer City Generation v. EPA. Dan Farber's concise and pointed critique is here. It's not clear to me, however, that Dan's critique reaches the court's ultimate decision in the case to strike the regulations. He does not argue explicitly that the case was incorrectly decided under the law. And it seems at least possible that the court might still have overturned the regulation, even if it had been more restrained in expressing its opinion.
At least now the DC Circuit has provided EPA with clear parameters for rule-making on interstate air pollution. So, when it tries again - for at least the fourth time - to regulate pollution from upwind states to protect air quality in downwind states, it will have a better chance of surviving judicial review. That's not to say that I disagree with any of Dan's critique or approve of the court's aggressive over-reaching. I don't. I'm just looking for a silver lining. On the other hand, EPA probably thought it knew exactly what it needed to do to promulgate an interstate air pollution rule that could survive judicial review based on the last three rules that the court struck down.
On a separate matter, Dan Farber has also posted a handy side-by-side comparison of Republican and Democrat party platforms concerning energy and the environment (here). I would have referenced it in a separate post, only I just don't think party platforms are very significant (although I appreciate that others, e.g., here, think they give insights into a party's aggregate ideology and governing strategy).