While the president can fire other high-ranking executive officials at will, federal law bars the president from terminating the postmaster general under any circumstances. Biden can attempt to oust DeJoy indirectly, but that option is fraught with legal uncertainties, and certain to trigger Republican complaints of norm busting. Unless the president is willing to take a significant legal risk, DeJoy will remain in control for months or years to come.
To oversee USPS’s activities, Congress established a nine-member board of governors who are nominated by the president and confirmed by the Senate. No more than five members of the board may belong to the same political party. Once confirmed to the board, governors can only be removed by the president “for cause”; that means their jobs are safe unless the president can show that they engaged in malfeasance or extreme neglect of duty. The board of governors, in turn, selects the postmaster general, who is not subject to Senate approval. And once appointed, the postmaster general can only be removed by the board, though it need not justify its decision.
This structure, in short, is why Louis DeJoy remains postmaster general under Biden. The board of governors is dominated by Trump appointees; Senate Republicans refused to confirm President Barack Obama’s nominees to the board, leaving vacancies that Trump promptly filled. Today, there are four Republicans and two Democrats on the board, plus three vacancies. One Democrat, Ron Bloom, is serving a holdover term which means Biden can replace him at any time. Thus, Biden can fill four seats on the board of governors—a move that would flip the board, giving Democrats a 5–4 majority. The new president can then urge the Democratic members to remove DeJoy, which they can do by a majority vote.
Filling these vacancies is the simplest way for Biden to get rid of DeJoy, though there is no guarantee that it will actually work.