text:  That was the end of the debate, right? We've been subjected to a whole lot of exchanges where Biden lost his train of thought or was rambling or just seemed low energy. And then he gets that question directly asked, whether you're up to serve until you're 86 years old. And he rambled again and ended up not really having a particularly coherent answer or a particularly sharp answer. That was not a good moment for Biden, despite the humor at the end of that exchange that I think offered some rare levity in the debate.