On a debate stage filled with candidates who sounded like they favored open borders, wanted to to eliminate private health insurance, and intended to enact laundry lists of expensive new government programs, an alternative who staked out somewhat more moderate positions while also deftly reminding the audience of his role serving for eight years as second-in-command to a hugely popular recent president should have done well. It’s no doubt why he’s been doing so well up to now.

But it’s hard to see how that continues. Biden has always seemed a little shaky, a little lacking in focus and discipline. He has a reputation as a one-man gaffe machine because he often speaks before he thinks. He’s a politician of impulse and instinct, and his impulses and instincts have frequently been just a bit … off. But now, entering his late 70s, gearing up for what could be a 12-month battle with a range of talented Democrats, many of whom are sharper and more nimble than he is and who are perfectly at ease on the far side of the “woke” divide — now Biden is just plain out of his depth. Or so it appeared on Thursday night.

His answers to questions posed by the debate moderators were generic Democratic-candidate word salads sprinkled with biographical boilerplate and often nonsensical references to the diabolical Trump and the saintly Obama. And that’s when he was free to say anything he wanted, without an opponent pushing back and cornering him. When the latter happened, it produced an ugly, self-protective mess of verbiage.