Reminder: America's energy giants are among the most profitable companies on earth, and they have billions to buy state legislatures in order to destroy environmental regulations.  But these energy companies also have state attorneys general in their pockets, and they are leading the charge in constantly suing the EPA with the goal of having the Supreme Court chip away until nobody is left protecting the environment.
The letter to the Environmental Protection Agency from Attorney General Scott Pruitt of Oklahoma carried a blunt accusation: Federal regulators were grossly overestimating the amount of air pollution caused by energy companies drilling new natural gas wells in his state.

But Mr. Pruitt left out one critical point. The three-page letter was written by lawyers for Devon Energy, one of Oklahoma’s biggest oil and gas companies, and was delivered to him by Devon’s chief of lobbying.

“Outstanding!” William F. Whitsitt, who at the time directed government relations at the company, said in a note to Mr. Pruitt’s office. The attorney general’s staff had taken Devon’s draft, copied it onto state government stationery with only a few word changes, and sent it to Washington with the attorney general’s signature. “The timing of the letter is great, given our meeting this Friday with both E.P.A. and the White House.”

Mr. Whitsitt then added, “Please pass along Devon’s thanks to Attorney General Pruitt.”

The email exchange from October 2011, obtained through an open-records request, offers a hint of the unprecedented, secretive alliance that Mr. Pruitt and other Republican attorneys general have formed with some of the nation’s top energy producers to push back against the Obama regulatory agenda, an investigation by The New York Times has found.

Attorneys general in at least a dozen states are working with energy companies and other corporate interests, which in turn are providing them with record amounts of money for their political campaigns, including at least $16 million this year.
So yes, big energy is buying state attorneys general too.  Multiple states suing the government in multiple circuit court jurisdictions is the fastest way to get these cases before SCOTUS.  They just need one ruling in their favor that finds that the EPA has overstepped its authority, and the game (and our environmental health) is over.

The case on EPA mercury regulations under the Clean Air Act, which the Supreme Court will hear soon and issue a ruling on in June, could very well be the one Big Energy is looking for.