A stutter does not get worse as a person ages, but trying to keep it at bay can take immense physical and mental energy. Biden talks all day to audiences both small and large. In addition to periodically stuttering or blocking on certain sounds, he appears to intentionally not stutter by switching to an alternative word—a technique called “circumlocution”—­which can yield mangled syntax. I’ve been following practically everything he’s said for months now, and sometimes what is quickly characterized as a memory lapse is indeed a stutter. As Eric Jackson, the speech pathologist, pointed out to me, during a town hall in August Biden briefly blocked on Obama, before quickly subbing in my boss. The headlines after the event? “Biden Forgets Obama’s Name.” Other times when Biden fudges a detail or loses his train of thought, it seems unrelated to stuttering, like he’s just making a mistake. The kind of mistake other candidates make too, though less frequently than he does.

During his 2016 address at the American Institute for Stuttering, Biden told the room that he’d turned down an invitation to speak at a dinner organized by the group years earlier. “I was afraid if people knew I stuttered,” he said, “they would have thought something was wrong with me.”

Yet even when sharing these old, hard stories, Biden regularly characterizes stuttering as “the best thing that ever happened” to him. “Stuttering gave me an insight I don’t think I ever would have had into other people’s pain,” he says. I admire his empathy, even if I disagree with his strict adherence to a tidy redemption narrative.

In Biden’s office, as my time is about to run out, I bring up the fact that Trump crudely mocked a disabled New York Times reporter during the 2016 campaign. “So far, he’s called you ‘Sleepy Joe.’ Is ‘St-St-St-Stuttering Joe’ next?”

“I don’t think so,” Biden says, “because if you ask the polls ‘Does Biden stutter? Has he ever stuttered?,’ you’d have 80 to 95 percent of people say no.” If Trump goes there, Biden adds, “it’ll just expose him for what he is.”