Sen. Bernie Sanders (I-Vt.) (Theo Wargo/Getty Images)

Sen. Bernie Sanders (I-Vt.) on Wednesday urged supporters dejected over the prospect of four years of President Donald Trump to mobilize against bigotry and hold Trump accountable for campaign promises to take on Wall Street and protect entitlement programs.

“When we stand together by the millions, we can stop Mr. Trump or anyone else from doing bad things,” Sanders told a crowd of 1,500 mostly young people at George Washington University in the District.

“We will not be involved in the expansion of bigotry and racism, sexism, homophobia,” he said later, interrupted by cheers.

In that spirit, he urged Trump to rescind the appointment of Stephen K. Bannon as one of his top aides, joining scores of Democratic officials who say the former head of BreitbartNews has a history of remarks disparaging minorities and appealing to white nationalists that disqualifies him from a White House job.

“A president of the United States should not have a racist at his side,” said Sanders, to the loudest applause of the night. “Unacceptable.”

Sanders, who was selected earlier in the day to serve in the Senate Democratic leadership, said he would support Trump on issues on which they agree, including renegotiating trade deals, offering paid maternity leave and protecting Social Security, Medicare and Medicaid from budget cuts.

“When he comes up with ideas that make sense for working people, I think we should be working with him,” Sanders said. “When he is racist and sexist and homophobe and Islamophobe, I think we’re going to be vigorously in opposition. I think on climate change, there is no compromising.”

Sanders cautioned his supporters against dismissing Trump, calling bigots a “very small minority” of the president-elect’s support base.

“The majority of people in this nation are not racist, they are not sexist, they are not homophobes,” Sanders said. “What Trump tapped was there are millions of working-class people totally ignored by the media.”

The GWU event was part of Sanders’s national tour to promote his new book. He was scheduled to speak Thursday at Johns Hopkins University in Baltimore.

At a question-and-answer session after Trump’s remarks, Washington Post columnist E.J. Dionne asked whether the 75-year-old senator would run again for president, eliciting applause and cheers of “Bernie!”

Sanders demurred.

“After what appeared to be a never-ending campaign in 2016, the last thing the American people are worried about now is who is going to run in 2020,” Sanders said.