The clock had just struck 1:15 p.m. on Wednesday when the justices, who had been in the courtroom since 10 a.m., finally appeared at a loss of what else to ask U.S. Solicitor General Elizabeth Prelogar about “Chevron deference.”

After more than three hours of rapid-fire questioning, over the course of two separate hearings, it seemed like all that could be said had been said about whether to overturn the “foundational” doctrine of administrative law, as Prelogar had called it.