Mike Blake / Reuters

Joe Biden had to know the question was coming.

In each Democratic debate so far, the former vice president has faced tough questions about his position on desegregating schools via busing, and tonight in Houston was no different. The moderator Linsey Davis noted that Biden had told a reporter in 1975 that he did not feel responsible for what people did 300 years ago. “As you stand here tonight, what responsibility do you think that Americans need to take to repair the legacy of slavery in our country?” Davis asked.

That phrasing was actually a gift—a chance for Biden to pivot away from the sticky specifics of busing and make a lofty statement about race. But Biden didn’t take it.

Instead, he offered a bizarre, rambling, and incoherent answer that barely responded to Davis, mixing racial justice, education policy, and a healthy dose of who-knows-what. The dizzying nature of the reply can only be grasped by reading it in full:

Look, there’s institutional segregation in this country. And from the time I got involved, I started dealing with that. Red lining, banks, making sure we are in a position where—look, you talk about education. I propose that what we take is those very poor schools, the Title I schools, triple the amount of money we spend from $15 to $45 billion a year. Give every single teacher a raise to the equal raise of getting out of the $60,000 level. Number two, make sure that we bring in to help the teachers deal with the problems that come from home. The problems that come from home. We need, we have one school psychologist for every 1,500 kids in America today. It’s crazy. The teachers are—I’m married to a teacher, my deceased wife is a teacher. They have every problem coming to them. We have to make sure that every single child does, in fact, have 3-, 4-, and 5-year-olds go to school—school, not day care, school. We bring social workers into homes with parents to help them deal with how to raise their children. It’s not that they don’t want to help; they don’t know quite what to do. Play the radio, make sure the television— excuse me, make sure you have the record player on at night, the phone—make sure that kids hear words, a kid coming from a very poor school—a very poor background will hear 4 million words fewer spoken by the time they get there.

That’s a word salad even Sarah Palin would have hesitated to serve. Each individual component made some sense in isolation, even the line about playing the radio or TV: Experts say it’s useful for children to hear spoken language to help them develop their own. But the way Biden phrased it, complete with an archaic mention of record players, just reinforced the overall incoherence and randomness of his response.

That’s an especially serious problem because there’s another question that Biden knew was coming Thursday, though it was mostly posed through passive-aggressive comments: Is he simply too old and off his game to be the Democratic presidential nominee? Rambling rants about turntables certainly don’t help put such concerns to rest.

But Biden didn’t stop there. Perhaps he sensed how poorly the answer had gone and was flailing, but he then decided to answer several foreign-policy questions that had been asked of his rivals earlier in the night.

“No, I’m going to go like the rest of them do, twice over,” he said when the moderators tried to stop him—the flash of anger a rare break in his unfailing politesse on the debate stage.

“By the way, in Venezuela, we should be allowing people to come here from Venezuela. I know [President Nicolás] Maduro. I’ve confronted Maduro. Number two, you talk about the need to do something in Latin America. I’m the guy that came up with $740 million, to see to it those three countries, in fact, changed their system so people don’t have a chance to leave. You’re all acting like we just discovered this yesterday.”

Now Biden wasn’t just rambling—he was the angry old man demanding his rivals, and the moderators, get off his lawn. It was a disastrous answer. Nor was that the only time on Thursday when Biden seemed to be spinning his wheels as he searched for an answer.

Biden faced other tough jabs from his opponents throughout the night. Most pointedly, Julián Castro accused Biden of forgetting a statement about health care. “Are you forgetting what you said two minutes ago?” Castro said, not very subtly broaching the age question. “Are you forgetting already what you said just two minutes ago? I can’t believe that you said two minutes ago that they had to buy in and now you’re saying they don’t have to buy in. You’re forgetting that.”

(As New York’s Adam K. Raymond pointed out, though, it was Castro who was mistaken—and Biden who’d been consistent.)

Will any of this matter? It’s anyone’s guess, but the evidence so far suggests it might not. There’s an active conversation about whether Biden simply isn’t up to the job, especially in the press, but so far his polling has remained remarkably durable. While there’s heavy churn among his rivals, with the field starting to sort out into some clear tiers, Biden has consistently led by a wide margin. Yet he also cannot put the questions to rest, and with every episode like his record scratch giving more ammunition to doubters, the risk is that the accumulation of missteps starts to drag his numbers down.

If there is one silver lining for Biden, it’s that the misstep came near the end of the debate. Just a few minutes later, he was the first candidate to answer a question about overcoming adversity, and he talked about the death of his wife and daughter in a car crash just after he was elected senator, and the death of his son Beau Biden from brain cancer in 2015. These are tales that Biden has told before, and he tells them well and movingly.

“We’ve all went through that, in some form or another,” Biden said. “For me, the way I’ve dealt with it is finding purpose. And my purpose is to do what I’ve always tried to do and stay engaged in public policy, but there’s a lot of people that have gone through a lot worse than I have get up every single morning, put their feet one foot in front of the other, the real heroes out there.”

That answer goes a long way to showing why the former vice president remains so popular with so many Democratic voters. It was Biden at his grandfatherly best—just moments after Biden at his grandfatherly worst.

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