“It’s like Forrest Gump won the presidency,” said a Republican congressman in a conversation that Erick Erickson described last week on The Resurgent. The congressman went on, adding profanities, not reproduced here: “But it’s an evil, really stupid Forrest Gump. He can’t help himself. He’s just an idiot who thinks he’s winning when people are bitching about him.”

This comes from a congressman who, Mr. Erickson said, regularly appears on Fox News to defend President Trump. The same congressman used a barnyard epithet to describe how the president treated his fellow Republicans, and concluded, “if we’re going to lose, we may as well impeach the —” well, as we used to say during Watergate, expletive deleted.

They make a wild duet, Gump and Trump, like the set of identical cousins on the old “Patty Duke Show”: “One pair of matching bookends, different as night and day.” But one important difference between the fictional Forrest Gump as played by Tom Hanks in the 1994 film and the president of the United States, as played by Donald Trump in 2018, is that Gump is a fundamentally modest man, painfully aware of his own limitations. “I am not a smart man,” he says. “But I know what love is.”

Mr. Trump says, in contrast, “I’m like, smart.” Does he know what love is? “You know, I don’t want to sound too much like a chauvinist, but when I come home and dinner’s not ready, I’ll go through the roof, O.K.?” he said in the same year “Forrest Gump” was released. So there’s that.