I say this as someone who pushed back so hard on the "Biden is too old" thing for years, and I never thought he was too old until Thursday night. But now I do. It wasn't "one bad night", it was the worst possible night at the worst possible moment. It wasn't "a bad debate", there has never been a worse debate performance by any other candidate since we've started showing them on TV. I've never voted Republican in my life, not even for a moderate. But if he was running against anyone but a coup …