West Virginia Attorney General Patrick Morrisey says Solicitor General Elbert Lin is leaving soon to return to the private sector.
Morrisey announced Lin's impending departure Thursday.
Lin has overseen lawsuits filed by Morrisey's office against federal agencies, including the U.S. Environmental Protection Agency over then-President Barack Obama's efforts to reduce emissions from existing power plants. The Supreme Court last year blocked the Clean Power Plan from taking effect while a federal appeals court considers whether it was legal.
Morrisey, a Republican, is running in next year's U.S. Senate race, seeking the seat now held by Democrat Joe Manchin.