http://insider.foxnews.com/2018/11/08/judge-napolitano-matthew-whitaker-does-not-qualify-under-law-be-acting-attorney-general

Napolitano said Whitaker, however, is not legally qualified for the role of acting attorney general because of "very precise laws" written by Congress in the wake of the Watergate scandal.

He said there are only three ways someone can become acting attorney general: if they are the deputy attorney general and the president signs an executive order to make them acting attorney general, if they are already at the Justice Department in a job that both required and received Senate confirmation or if the Senate in in recess, they can be a recess appointment.

He said none of those apply in this case.