Liberals from November 2016 until June 2020: The Department of Justice enjoys independence, both legally as well as normatively, from the White House and President. The President should only supervise investigations and prosecutions at the broad policy-making level (via statutes and regulations) and by appointments in the normal course of rotation in office, through retirements and resignations. If the President wants to know the details of ongoing investigations and prosecutions, he can read about them in the newspapers like anyone else. The unitary executive theory is alien to our legal system—a phony doctrine made up by the Federalist Society.
Liberals after June 2020 Publication of the Strzok Memorandum in the Flynn Matter: Of course, the President should be apprised of the details of all ongoing investigations—even if they involve the opposition party’s candidate and his confidantes. No one is above the law! The President is supposed to comment about how to staff those investigations. And the Vice President is supposed to put forward novel legal theories (e.g., the Logan Act) in order to help the investigation/prosecution (of his future opponent). These are not disqualifying conflicts: such conflicts are built into the Constitution. The Vice President is part of the Executive Branch and has a role in active Justice Department investigations—even if that involves the opposition. The unitary executive includes the Vice President. The Unitary Executive …
To put it another way … the active involvement of the Attorney General and Main Justice in overriding the decisions of subordinates and career civil servants is bad, particularly if all the facts are known and when it is done in public. But the Vice President’s putting forward novel legal theories to move an investigation of the opposition forward is … perfectly normal … especially when done in secret. Makes complete sense.