This afternoon the US Supreme Court on a 5-4 vote issued a stay of the application of the Clean Power Plan to emitters (one example of the stays is here). They contradicted a lower court decision not to issue a stay pending a final legal ruling, so now the requirements are blocked for a period of months or more. The lower court has to issue its ruling, and then the inevitable appeal will be made by the losing party, and the Supreme Court will almost-inevitably accept the appeal and go through its own process. It won't end before the next President takes office.
That's obviously bad news for efforts to fight climate change, delaying initial requirements for taking place. The real question though is what does it tell us about the likely final outcome at the Supreme Court. Stays are generally issued based on four criteria:
(1) the likelihood that the party seeking the stay will prevail on the merits of the appeal; (2) the likelihood that the moving party will be irreparably harmed absent a stay; (3) the prospect that others will be harmed if the court grants the stay; and (4) the public interest in granting the stay.
It's that first criterion that can set back global efforts on climate change. Courts do a balancing of the criteria, so if the Supreme Court majority weighed the other three strongly against the EPA, then they may be only somewhat doubtful of the Plan's legality. On the other hand, EPA argued that the early stages of the Plan place few restrictions on emitters (the emitters disagreed, saying they have to plan for outcomes many years in advance).
This is a situation where the way you argue at one stage of a case may not necessarily help you later. The winning side hopes the Court ignored their own arguments when it came to potential harm and listened to their arguments on the merits, and the losing side hopes the reverse is true.
It's still very unfortunate. If the Clean Power Plan gets thrown out, then a Democratic Party president will seek some regulation that can partially replace the Plan. A Republican president will doubtless seek to do absolutely nothing, and then face lawsuits by environmental groups and by some states for failure to apply the Clean Air Act. Those lawsuits will take a number of years to move forward, a loss of time that we can't afford.
UPDATE: some more bad news, from the NY Times: "The 5-to-4 vote, with the court’s four liberal members dissenting, was unprecedented — the Supreme Court had never before granted a request to halt a regulation before review by a federal appeals court." That makes it even more likely that the majority is ready to shoot the law down - they'd otherwise be hesitant to take an unprecedented step.
One consolation is that the constitutional arguments against the law are so silly that even this conservative Court is unlikely to adopt them. It's the statutory interpretation arguments that are more dangerous, and they're most likely to limit the Plan's application, not kill it entirely.
Harvard law professor Larry Tribe, known as a liberal in some circles, makes the invalid constitutional arguments, and it's not the first time he's sought to take down environmental protections. I don't see how his legal philosophy could possibly be appropriate for a judicial appointment by a Democratic president.