The firing of Jeff Sessions and his replacement on an interim basis by a man who has expressed open hostility to the Mueller investigation and in whose loyalty President Trump has expressed confidence marks a major moment in the course of the Russia investigation.
It is a profoundly dangerous moment: The president fired the attorney general, as he once fired the FBI director, for plainly illegitimate reasons: because the attorney general acted appropriately on an investigative matter in which Trump himself has the deepest of personal interests.
Trump does not even pretend there are other reasons. He removed the attorney general because the attorney general did not protect him from investigation.
Yes, the president has the raw power to do this. But as was the case with the firing of James Comey, it is an abuse of the power he wields.