The U.S. Court of Appeals for the D.C. Circuit has punted again on ruling in a case challenging the Clean Power Plan.

An order from the court Friday leaves the parties, a group of Republican states and the Environmental Protection Agency, along with environmental groups and trade associations, in the legal limbo they’ve inhabited since the court heard oral arguments en banc last year. The order holds the case in abeyance for 60 days, and asks the parties to file briefs by May 15 on whether it should halt the case indefinitely or remand to the EPA.