The U.S. Supreme Court spent more than three hours Wednesday debating fundamental questions about the role of the courts, Congress and federal agencies as the justices heard a pair of challenges to a bedrock doctrine of administrative law known as “Chevron deference.”

During back-to-back hearings, Justices Neil Gorsuch and Brett Kavanaugh led the attack on the influential Chevron doctrine, which sets the ground rules for legal challenges to federal agency actions.