As early as last fall, Trump was talking privately with aides about the threat Biden posed: “How are we gonna beat Biden?” he would ask. When reassured that the moderate Biden would never defeat several of his more liberal rivals, Trump has pushed back: “But what if he does?”…

Trump’s mockery of Biden belies a belief that the former vice president is a true political threat, according to a Republican strategist close to the Trump campaign. “The candidates he doesn’t talk about, it’s a signal that he doesn’t take them seriously,” this person said.

“We have had a number of conversations about potential challengers, and Biden has been at the top of the list because of his polling numbers,” said a Republican lawmaker who talks frequently with the president. “He is seen as one of the most difficult potential challengers because of his appeal to independents and his likable style.”