The Supremes have decided to accept an industry/US Chamber appeal of a lower court decision saying the EPA was "unambiguously correct" when it used regulating greenhouse gases for motor vehicles as a trigger to begin regulating emissions by power plants. They refused to consider broader questions, including reconsideration of their 2007 decision that effectively mandated the beginning of EPA regulation. The EPA also interpreted legal requirements of the Clean Air Act to allow them to focus only on major polluters - the forces of darkness tried to make a poison pill of the law by forcing them to regulate everybody, and AFAICT that's been shut down.
This issue involves arcana of the CAA, much of it beyond my area. I can just say that it takes only four of the nine supremes to accept an appeal but it takes five to win. The original 2007 vote was 5-4. Granting cert to consider the appeal doesn't necessarily indicate a change in the vote count, but it does indicate that at least four think they've got a chance to ruin the global environment.
While it's legal arcana, the environmental implications are huge. That the US Chamber is again choosing the fossil fuel industry interests over the green business interests shows its dysfunction in failing to represent American businesses.