A strange departure for a candidate who’d wisely trained his fire on Trump up to this point. Sanders took a hard shot at Bloomberg yesterday…

The simple truth is that Mayor Bloomberg, with all his money, will not create the kind of excitement and energy we need to defeat Donald Trump. pic.twitter.com/9azeuWjLap

— Bernie Sanders (@BernieSanders) February 16, 2020

…so Bloomberg took a shot of his own — not at Bernie but at his boorish Internet cult, which advocates zealously for their man:

We need to unite to defeat Trump in November. This type of "energy" is not going to get us there. https://t.co/bPuUZMs2d6 pic.twitter.com/Tdp6mpWjcX

— Mike Bloomberg (@MikeBloomberg) February 17, 2020

Populism craves messiahs and Sanders’s more excitable fans spend a lot of time online protecting their chosen one. The intensity of their devotion has been written about lots lately, inspired by the backlash the Nevada Culinary Union received when they put out an informational flier noting that Bernie’s Medicare for All plan would mean the end of their union-provided health-care coverage. (That issue has dogged Sanders in the past, leading him to add a carve-out to his M4A proposal for unions.) The Culinary Union has tens of thousands of members and is tremendously influential in Nevada politics; that flier poses a real risk to Sanders’s chances to win the caucuses. Berniebros didn’t react well to it, but then they rarely do.

With union leaders complaining of harassment and the media (and Joe Biden) taking an interest, Sanders had to issue a perfunctory statement reminding everyone that harassment is bad mmkay:

“Harassment of all forms is unacceptable to me, and we urge supporters of all campaigns not to engage in bullying or ugly personal attacks,” Sanders, a front-runner in the Democratic primary race, said. “Our campaign is building a multi-generational, multi-racial movement of love, compassion, and justice. We can certainly disagree on issues, but we must do it in a respectful manner.”

That’s the inspiration for the Bloomberg ad. But … who’s the audience for it? Most Democratic voters have no clue about this drama and doubtless wouldn’t care if they did. Posting the ad to Twitter is a weird choice as well given how Very Online so many of Bernie’s fans are. They’ll see it and feel antagonized; how many prospective Bloomberg voters will see it and feel encouraged to vote for Mike because of it? I could understand if Bloomy were aiming it at members of the Culinary Union, nudging them to punish Sanders at the caucuses by voting for him instead. But Bloomberg’s not on the ballot in Nevada.

Even under the best political circumstances, the Bernie cult would be the group least likely to turn out in the fall for Bloomberg as nominee. But he’d get a few, purely on “Anyone But Trump” grounds. Attacking Sanders will shrink that number, although attacking him is probably unavoidable as the race goes on. Attacking Sanders’s fans, though, is apt to shrink it even more and is wholly avoidable. What is he thinking? Just showing that he’s a “fighter,” willing to come right at the dregs of the DSA? Trying to suck media oxygen out of the room for Biden, Buttigieg, and Klobuchar by giving the press something Bloomberg-related to write about? I don’t get it.