DOJ policy that a sitting president cannot be indicted is the only reason why Trump isn't in the dock right now.
BUCK: Let me just stop. You made the decision on the Russian interference [conspiracy]. You couldn’t have indicted the president on that. And you made the decision on that. But when it came to obstruction, you threw a bunch of stuff up against the wall to see what would stick, and that is fundamentally unfair.
MUELLER: I would not agree to that characterization at all. What we did is provide to the attorney general in the form of a confidential memorandum our understanding of the case, those cases that were brought, those cases that were declined, that one case where the president cannot be charged with a crime.
BUCK: Okay, but the … could you charge the president with a crime after he left office?
MUELLER: Yes.
BUCK: You believe that he committed … you could charge the president of the United States with obstruction of justice after he left office?
MUELLER: Yes.
There it is. Mueller confirms that Trump can be indicted the instant he leaves office. In the meantime, its time for Congress to do its duty and remove him from office via impeachment.