Barr gave him a chance to resign. He refused. So Barr had Trump fire him. Trump has the authority for sure. Barr probably does as well. But Trump definitely does. There is nothing messy. On Monday he will not be there.
The issue is not and WILL NOT the process of getting him out of his position, it will be WHY they let him go.
Mark my words — the Democrats will say that this is an insider attempt to STOP a legitimate investigation into Trump’s corruption.