It's not necessary for the federal government and the city to come to an agreement before Ms. Rawlings-Blake leaves office. In fact, it might be preferable for Ms. Pugh to have her fingerprints on the deal — she will be the one who will have to see it through, and she should have some ownership over it. But it is absolutely imperative for it to be finalized before Jan. 20, the day Mr. Trump is to be inaugurated. Once a deal is accepted by the courts, a federal judge will have the power to see that it is enforced, no matter who is attorney general. But if that doesn't happen before Mr. Trump arrives, Baltimore's police reform effort will be at risk.