Instead, these insiders describe a campaign that has dispensed with the largely positive tone which characterized Sanders' 2016 presidential run in favor of a combative, grievance-driven one. They say it is led by a team of "true believers" who have little experience with presidential campaigns, are too enthralled by Sanders to question or challenge him, and who knowingly wield swarms of angry, harassment-happy pro-Sanders social media users like any other tool in the campaign toolbox for a candidate who, despite claims to the contrary, is perfectly fine with it.

"That's the tone that has been set by campaign leadership," said one Democratic strategist, a Bernieworld veteran. He pointed to the campaign's frequent use of email fundraising solicitations which warn supporters that the "establishment" is trying to keep a rigged system in place by stopping Sanders' candidacy.

He noted that the rhetoric coming from the top of Sanders' campaign had taken a more combative turn since October, when Elizabeth Warren's slide in the polls, Sanders' heart attack, and Rep. Alexandria Ocasio-Cortez's endorsement began to propel him back into the top echelons of the Democratic race.

"Clearly, they think it's a winning strategy. Beforehand, people just looked at the campaign as being kind of a little bit mean and nasty, but it's gone up a notch and I think they probably feel justified." But it's not just bombastic fundraising emails that are driving some Sanders supporters to attack, threaten, and harass those deemed to have maligned the Senator in one way or another. In many cases, the victims of what online disinformation experts call "swarms" or "dogpiles" have found themselves singled out for abuse by those who take their cues from campaign staff and prominent surrogates.