Conservatives are understandably displeased with the Supreme Court after last week’s rulings, but as the season drew to a close the justices managed to deliver at least one bit of good news for opponents of excessive and burdensome government regulations. In the case of Michigan v. Environmental Protection Agency, the court was asked to consider the impact of new regulations on mercury, arsenic and acid gas emissions from conventional power plants and whether the rules were both “appropriate and necessary” to the core mission of the agency.

From the beginning, we knew this was going to be a tough case. Most of the liberals on the court are ready to jump onboard with any green energy schemes and anything which can give a black eye to fossil fuels will probably be looked upon with favor. After the initial arguments were heard a few months ago, SCOTUSblog examined the reactions of the justices and thought Michigan stood a chance but it was no sure thing.

The agency’s decision to regulate the emissions of mercury and other poisonous chemicals from the stacks of electricity-generating power plants that burn coal came out of the argument with clear support from only three Justices and possibly a fourth, offset by clear opposition from two and probably three others. That put into play the votes of Chief Justice John G. Roberts, Jr., and Justice Anthony M. Kennedy.

As the hearing unfolded, the Chief Justice got involved slowly but, after he joined in, went from somewhat skeptical to openly critical of whether the EPA had justified its approach to those utility plants. Justice Kennedy started out seeming to want to believe that the EPA had put itself on solid legal ground, but he, too, grew more hesitant about that as the argument progressed. If both wind up dissatisfied, the EPA at least may have to reconsider, and might lose altogether.

It didn’t wind up being nearly as complex as the author anticipated. In the end it came down to the usual 5-4 split with the liberals siding with big government and Kennedy jumping in on the side of stopping government overreach for a change. The plaintiffs argued that the EPA failed to take the crippling costs of the regulations and the short runway for implementing them into account and it looks like the majority found that to be the deciding factor, and that the costs vastly outweighed any potential benefits.

EPA interpreted §7412(n)(1)(A) unreasonably when it deemed cost irrelevant to the decision to regulate power plants. Pp. 5–15.

(a) Agency action is unlawful if it does not rest on a consideration of the relevant factors… EPA strayed well beyond the bounds of reasonable interpretation in concluding that cost is not a factor relevant to the appropriateness of regulating power plants. Pp. 5–6.

(b) “Appropriate and necessary” is a capacious phrase. Read naturally against the backdrop of established administrative law, this phrase plainly encompasses cost. It is not rational, never mind “appropriate,” to impose billions of dollars in economic costs in return for a few dollars in health or environmental benefits.

If you want to see some of the liberal hand wringing over this, just stop by the Washington Post.

The majority decision came from Scalia, joined by Roberts, Kennedy, Thomas and Alito. The dissent was given by Elena Kagan, joined (as usual) by Ginsburg, Breyer and Sotomayor. But the majority decision could serve as a key precedent going forward, as multiple states and power companies have similar suits lined up against the Obama EPA like 747s lined up for takeoff at an airport. The wording should be rather stinging for the EPA and sends a clear message. Their actions have been deemed “irrational” at the Supreme Court, and clearly inappropriate. The underlying message is that you can’t simply wave a magic wand and proclaim an end to all the “dirty” fossil fuels which can’t match up to the impractical emission standards of solar panels without paying any heed to how much it will cost to make the change and the impact on the nation’s power grid when they are unable to comply. There are also upcoming climate change regulations in various forms where proponents should now have to prove that the costs they impose have at least a real chance of delivering some direct value in return. Lots of action on that front is coming up in the next year or two.

I know this probably seems like a small thing compared to some of the other decisions which have come down, but trust me. This was a big win for the conservative cause today and provides at least some reason to celebrate as the Supremes ride off into the sunset until the next session.