Billionaires are in notably bad odor with many people on the left. Socialists have long held that large stores of private wealth are tantamount to violence against those in need. But regular nonradical folks not on the left are fed up, too. Howard Schultz’s potential independent White House bid is simply infuriating, and it’s maddening to feel helplessly tangled in the gilded web of global intrigue emanating from the president, his plutocrat dictator pals and America’s retail overlord, the philandering Jeff Bezos.

Thanks at least in part to Bernie Sanders and the sizzling rise of Alexandria Ocasio-Cortez, this dry wick has met a spark. Enthusiasm for radical leveling is whistling out of the hard-left fringe and blossoming into a mainstream mood.

Ms. Ocasio-Cortez’s policy adviser, Dan Riffle, contends that “every billionaire is a policy failure” (that’s the tagline on his Twitter handle) because “the acquisition of that much wealth has bad consequences” and “a moral society needs guardrails against it.” He’d like to see the 2020 Democratic primary contenders answer a question: Can it be morally appropriate for anyone to be a billionaire?

It’s a compelling litmus test. I’d also like to watch would-be Democratic nominees take it. However, I hope that they would stick up for the idea that it can be morally kosher to bank a billion and that the existence of virtuous three-comma fortunes is a sign not of failure but of supreme policy success.