West Virginia Solicitor General Elbert Lin, who led his state’s litigation fight against the Obama administration’s signature Clean Power Plan and oil and gas methane standards, is leaving his post, according to the state’s attorney general, Patrick Morrisey.

Lin, a Yale Law School graduate and a former clerk to Justice Clarence Thomas, has been rumored to be in line for a federal judgeship either at the district or circuit court level, but Morrisey said he is returning to the private sector. He was also a clerk to a conservative favorite, Judge William Pryor of the U.S. Court of Appeals for the Eleventh Circuit, who is on President Donald Trump’s list of potential U.S. Supreme Court nominees.