The U.S. attorney general may not withhold funding from a city in retaliation for maintaining “sanctuary city” policies, Hogan Lovells attorney Neal Katyal argued before the U.S. Court of Appeals for the Third Circuit on Wednesday.

Katyal, who was representing the Philadelphia city government, made his arguments just as U.S. Attorney General Jeff Sessions submitted his resignation at the request of President Donald Trump. No one at the argument mentioned Sessions’ departure.