Not the best scenario, because Rosenstein is in cahoots with Mueller.
The Number 3 official at Justice is Rachel Lee Brand, who has very good credentials and who I think would be on the side of the President (imagine that).
Trump can also fire Rosenstein, and if Brand is not his choice, he can perform a recess appointment next month.
And Brand own’t swear a blood oath to Donnie either, so she would be gone after a couple of months.
There's actually one person who would take that job in a heartbeat, and he's probably one of the last people most Freepers would want to see in the AG role:
Chris Christie.