It is customary for all “plum” job holders (appointments - ie, over SES 7) to be asked to resign at the start of a new administration.
Billy C, after all, ‘fired’ ALL of the US attys.
I believe the term is “to the victor belongs the spoils”.
Bush did this differently, and was savaged for it. His loss.
I want to see just who all the new “ Deputy and Assistant deputy Secretaries” will be. There is where the real mischief begins.
To be fair, Bush did replace all (or most) of the US Attorneys when he took office in 2001. What was different was that he also fired a few of those who he had hired, in the middle of his term. That action was somewhat unusual. There was, of course, nothing wrong with what he did(they do, after all, serve at the pleasure of the President), but it was unusual.