The Giuliani interview was, I think, intended as a threat, not only to Mueller, but to Attorney General Rod Rosenstein, who appointed him. Giuliani said pointedly that he doesn’t know Rosenstein and that his “good friend” Jeff Sessions, the attorney general, “should never have appointed Rosenstein.”

What’s more, Giuliani declared, “The two of them can redeem themselves, Sessions and Rosenstein. They should order the investigation over.”

Trump doesn’t need them to. He can order the investigation over. According to statute, Rosenstein must dismiss Mueller, not Trump — but an originalist reading of the Constitution would say that since Rosenstein and Mueller are both subordinates of the president, Trump has every right to fire them.

This is the great temptation for Trump.