“Can the President do that?”
No. Trump has many strengths, but legal scholarship is not among them.
But he knows how to hire good staff, and any pick he chooses to advise on LE matters, too include the Attny Gen, will be a heck of a lot smarter regarding LE matters than him, and most assuredly, more smart than anybody The Big Zero appointed or Cold Miss will appoint.
Trump is a success because he listened to his advisers.