It happens when an executive, after many years of striving, finally makes it into the corner office—and then immediately jettisons all the great leadership skills that got him or her there. The pure intoxication of power somehow trumps (yes, that was on purpose) all the teamwork, the collaboration, the thoughtful decision-making. The CEO becomes a one-man (almost always a man) band of action. Finally, he thinks to himself, I don’t have to pretend to listen to anyone. And the results speak for themselves. Famous sufferers of CEO disease include former Disney CEO Michael Eisner, Enron’s Jeff Skilling, Viacom’s Sumner Redstone, and Theranos’s Elizabeth Holmes. (The syndrome is not unknown in other realms, obviously.)

So there is no small irony in the fact that Bernie Sanders appears to have fallen victim to this affliction of corporate power-grabbers—despite his socialist background.

I have long admired Sanders’ campaign for its willingness to ask the questions that need to be asked, for its underdog nature, for its ability to bring a very disparate group of people together. It is also true that he has long been a lone wolf, the kind of person who did what wasn’t popular because he believed it was right.

But his refusal to acknowledge that the Democratic primary campaign is over—when it is—is an abdication of what his campaign once stood for. Sanders lost. He lost fair and square. And viewed through a leadership lens, his behavior looks like nothing more than an outbreak of CEO disease. In this fascinating article in Politico, it becomes clear that every one of Sanders’ recent—and increasingly combative—moves has come not from the team that together built a coherent and emotional message, but from Sanders himself.

“Every time Sanders got into a knife fight, aides say, they ended up losing,” the Politico story reads. “But they could never stop Sanders when he got his back up.”