My friend has a teenage son. He’s a good kid, well-behaved, impeccably mannered and exasperatingly unpredictable, as many teenagers are — a man one minute, a boy the next. My friend has schooled his son in the verities of life — be truthful, be reliable, be civil, be patient and, above all, be humble. Now, though, my friend does not know what to say. Donald Trump has left him silent.

There are many reasons to loathe Trump. His policies are mostly wrong, and even those that are right have been chaotically announced or implemented. He prescribes barroom oaths for an economy that needs thought and creativity. He would let the Earth bake rather than take the most rudimentary of steps to moderate global warming. He alienates allies and friends, embraces enemies and indulges in a noxious moral relativism in which, somehow, Russia and America are on the same level.

But it is my friend’s dilemma that best evokes what is so repellent about Trump. He is the winner who was supposed to lose. He is the bully in the fourth grade who never meets his match. He is the liar whose lies somehow don’t matter. He is the braggart who is never humbled. He refutes what Johnny Tremain was told and every child once instructed: “Pride goeth before a fall.” No, with Trump pride goeth before everything .

[The ‘best fortnight in a decade’ for conservatives? Uh-oh.]

Donald Trump is the most un-American of presidents. Think of Abraham Lincoln — “Honest Abe.” Will anyone ever call Trump “Honest Don”? Will he be known for his humility or for his lust for knowledge? Will tales be told about his industrious work habits or, as with Lyndon Johnson, his furious desire to end racial discrimination? What will Trump overcome?

(Sarah Parnass/The Washington Post)

Or George Washington. Could there ever be an equivalent of the Parson Weems tale about Trump’s honesty: “Father, I cannot tell a lie”? No, it would have to be “Father, some Mexican cut down the cherry tree.” Or Dwight Eisenhower and his chain-smoking determination on the eve of D-Day, or Ronald Reagan and his affable demeanor with a bullet in him, or George H.W. Bush, who left his cushy country club life and volunteered for war at the age of 18, or Franklin D. Roosevelt, standing on atrophied legs, the braces digging into his flesh, or Barack Obama, whose dignity in the face of Trump’s revolting “birther” taunts is now so sorely missed. Trump repudiates them all. He will leave no myth, just an odor.

Myths have a certain staying power because, really, they are aspirational — not always who we are, but always who we want to be. We see ourselves as good and generous. We believe we are a virtuous nation. There is no monarchy or dictatorship in our past. We have always been a democracy, and even our presidential palace is sometimes called “the people’s house.” I am aware, of course, of slavery and Jim Crow and enduring racism. I am aware, too, of the near-extirpation of the American Indians and the raw anti-Semitism that doomed many Jews fleeing Hitler. All of this is unforgivable, unforgettable too.

[Congress has the power to obtain and release Trump’s tax returns]

As a kid, I was a paperboy, and the walls of the place where we picked up our papers were plastered with pictures of former paperboys — some sports figures, some presidents, some military officers. Ike was one. Roy Campanella, the Brooklyn Dodgers catcher, was another and so was the “G.I.’s General,” Omar Bradley, the last of the five-stars. I used to study that wall, wonder about those men and whether I could ever be like them. I envision it now. There is no room for Trump there. He does not qualify. Never mind that he was never a paperboy. More important, he is no role model.

A father instructs. He raises a child to be good, to be honest, to tell the truth, to be humble, to be fair, not to be petty, to respect women, to accept fair criticism, to protect the weak and not to injure the injured, such as the bereaved parents of a son who died heroically in Iraq and a reporter with a physical disability. Trump teaches otherwise. He shows a boy that the manly virtues are for suckers, that the narcissism of youth should be cherished and that angry impulses have to be honored. Lots of men have failed as presidents, as Trump surely will, but few fail so dismally as role models. He’s a boy’s idea of a man. He’s a man’s idea of a boy.

Read more from Richard Cohen’s archive.