Years of accusations that Bernie Sanders has done too little to stop abusive behavior online by his supporters is resurfacing as a serious political problem for the Vermont senator, who faced attacks Wednesday in the Democratic presidential debate from rivals suggesting he deserves some of the blame.
"I think you have to accept some responsibility and ask yourself what it is about your campaign in particular that seems to be motivating this behavior more than others," rival Pete Buttigieg told Sanders in the Las Vegas debate.
Critics say Sanders has allowed a toxic and sometimes misogynistic culture to thrive among his most fervent backers despite his repeated statements that he does not approve of bullying or harassment.
Women in the leadership of a Nevada union that opposes his health care agenda were swarmed last week with vulgar and threatening emails, phone calls and Twitter posts. In the days following, Buttigieg, Joe Biden, Elizabeth Warren and Michael R. Bloomberg all questioned Sanders' commitment to curbing the provocations.
Warren, the senator from Massachusetts, was asked by an NBC moderator whether Sanders and his supporters were making it harder to unify in November. "We are all responsible for our supporters, and we need to step up -- that's what leadership is all about," she said.
Warren told NBC News on Tuesday that she was especially concerned about the online assault against Geoconda Arguello-Kline, secretary-treasurer of Nevada's powerful Culinary Workers Union, and the union spokeswoman Bethany Khan. Among other things, Sanders supporters called them "whore," "bitch," "corrupt" and "fascist" after the union released a flier criticizing the senator's "Medicare-for-All" plan as a threat to the union's health care benefits.
"That is not how we build an inclusive Democratic Party," Warren said. "We do not build on a foundation of hate."
At the debate, Sanders said 99.9% of his millions of Twitter followers "are decent human beings, are working people, are people who believe in justice, compassion and love, and if there are a few people who make ugly remarks, who attack trade union leaders, I disown those people. They are not part of our movement."
The senator added that African American women working on his campaign had been the subject of "vicious, racist, sexist attacks."
Buttigieg, the former mayor of South Bend, Ind., said he believed Sanders did not direct supporters' attacks on his critics. "But at a certain point, you've got to ask yourself, why did this pattern arise? Why is it especially the case among your supporters that this happens?"