Opponents of greenhouse gas regulation are likely cheering the Supreme Court's decision this morning to hear challenges to the EPA's legal authority to regulate certain greenhouse gas emissions.

The EPA concluded in 2009 that carbon dioxide and other greenhouse gases are pollutants dangerous to human health and welfare. Under a previous Supreme Court ruling, this "endangerment finding" meant that the Clean Air Act gives the EPA the power to regulate greenhouse gas emissions from new motor vehicles. The next year, the agency adopted a "Tailpipe Rule" for new cars and light trucks. Then, based on the agency's longstanding interpretation of the Clean Air Act, it also concluded that the Tailpipe Rule automatically triggered regulation of "stationary sources" of greenhouse gases like factories and power plants.

Industry groups and several states (with Virginia's Ken Cuccinelli acting as a key ringleader) challenged the EPA's rules. Cuccinelli, you may remember, abused his position as Attorney General to engage in a witch hunt designed to intimidate climate change scientists. In this case, he has attacked the EPA's underlying "endangerment finding," citing the manufactured right-wing "scandal" of "Climategate." Fortunately, the Supreme Court will not be considering this aspect of the appeals, which might have given Cuccinelli's claims some patina of legitimacy.

However, the Justices will be hearing challenges to the EPA's conclusion that it has the power under the Clean Air Act to regulate greenhouse gas emissions from stationary sources. The EPA's legal conclusions were upheld by a unanimous panel of the D.C. Circuit in a per curiam decision (per curiam is usually shorthand for "no duh") that included conservative Judge David Sentelle. According to the court, the EPA's interpretation of the Clean Air Act regarding stationary sources was "unambiguously correct" and "compelled by the statute."

We will have to wait until 2014 for oral arguments and a final decision. Then we will find out whether the Roberts Court will hand another victory to corporate interests.