The president’s habitual dishonesty justifies a rebuttable presumption that the truth is the opposite of whatever he says. That rule of thumb led many of his critics astray in this case, but it also illustrates the practical advantages of telling the truth, since Trump’s weaselly ways prolonged the Russia investigation and lent credence to the suspicion that he had something to hide.

“I have nothing to do with Russia,” Trump insisted in July 2016. Yet his lawyer, Michael Cohen, was working on a licensing deal for a Trump Tower in Moscow as late as the previous month and giving his boss regular updates on the project. When Cohen suggested to Trump that his statement was misleading, he told Mueller, Trump replied, “Why mention it if it is not a deal?”

A year later, when The New York Times reported that Trump’s son, son-in-law, and campaign chairman had met in June 2016 with a Russian lawyer promising “dirt” on Hillary Clinton, Trump edited a public statement about the meeting, excising any reference to that offer. When his communications director, Hope Hicks, suggested that Trump come clean about the motivation for the meeting, he told her, “You’ve given a statement. We’re done.”