But it was, finally, the lies that undid Johnson. He lied about big things and about little things, and he even lied about things that he didn’t need to lie about, as though he were only keeping in practice, Clinton-style. The U.K. parliament is unlike our Congress in that it actually makes some effort to participate in the governance of the country, and, for that reason, it continues to have a few shreds of institutional self-respect, which Congress happily gave up long ago. Johnson got away with lying to his constituents from time to time, just as he had once got away with periodically lying to his readers in the Telegraph, but Parliament took being lied to seriously. Johnson was subjected to a humiliating no-confidence vote that left him wounded and weak enough to be knocked off by the exposure of yet another lie, in this case about his appointing a political ally accused of sexual misconduct, Chris Pincher, to a party leadership position with foreknowledge of the allegations. Johnson probably didn’t really need to lie about that affair: Pincher already had resigned from Johnson’s government, and Johnson might as easily have told the truth — that he knew about Pincher’s behavior, was confident that he would not do it again, and wanted to give him a second chance. (Assuming that is more or less the truth.) But instead of sharing a little in the pain and taking responsibility for his own decision, he tried to insulate himself entirely from the situation.

That was dishonesty, true, but it was also cowardice.

The practical problem with habitual liars such as Boris Johnson is not that we are offended by their dishonesty (although we should be) but that they end up being impossible to work with. There aren’t a lot of contracts and ironclad deals in real-life politics, which is a game of negotiation and understanding that ultimately is based on trust. That is true for relations between rival politicians and rival parties, but it also is true for people who are on the same side and trying to cooperate.

The institutions of the free world run on trust, and Boris Johnson, in spite of his many excellent qualities, is a man not to be trusted.

That is a lesson that we Americans would benefit from learning.