Biden took his energy drink, or something. He came out on fire. He was sober, direct, returning volleys from the two lefties on either side of him. “For a socialist you have a lot more faith in corporate America than I do,” he said to Sanders.

But a half-hour into this third Democratic debate, many Democrats had to be wondering: Can he go three hours? It’s our own collective ageism.

He did, closing with his most appealing side: his humanity and vulnerability. After the El Paso shootings, Trump showed he couldn’t even pass the base test of a human being, demonstrating a smidgen of empathy. He couldn’t even fake it. Not for a minute. Biden bleeds empathy. What’s appealing about him is what my colleague Jennifer Senior called “the bartender aspect” of his character, in her review of his book on the loss of his son Beau.

Progressives looking for someone who will bring big structural changes should remember that we are electing not just a president, but an executive branch. I have no doubt that Biden would sign any kind of advanced legislation that can get by the Neanderthals holding the Senate back in the last century.

Waiting for Uncle Joe to collapse is not a winning strategy. Most of the other candidates in Thursday’s debate seemed to get that. O’Rourke had his best night. This is the rare politician who’s not afraid to let it rip, the b.s. valve turned off. Kamala Harris is brilliant, and would crush Trump in a debate. “You can go back to watching Fox News,” was her line that should be on bumper stickers soon. And on the shootings, she said of Trump: “He didn’t pull the trigger but he’s certainly been tweeting out the ammunition.”

For the two of them, though, it may too late: both Hillary Clinton and Donald Trump led at this stage in the polls four years ago.

Pete Buttigieg, born in 1982, nearly a decade after Biden entered the Senate, makes a pitch for generational change, citing John F. Kennedy and Barack Obama. He’s got the right song in the wrong presidential year. Remember the guy who specifically called for passing the generational torch in an earlier debate? Me neither. (It was Representative Eric Swalwell.)