COLUMBIA, S.C. — Bernie Sanders hit back Saturday at moderate Democrats unhappy that he's contesting the party's presidential nomination again.

"I want to say a few words about an interesting event that was held in Charleston earlier this week sponsored by a national organization called Third Way, that represents the corporate wing of the Democratic Party and a group that receives a substantial amount of their support from Wall Street," Sanders told the South Carolina Democratic Party convention.

"At this Third Way meeting I was called, 'an existential threat' to the Democratic Party," he said. "Now why am I an existential threat? Well, maybe it's because my administration will fight to take on the insurance companies and the drug companies and pass a 'Medicare for All' single-payer program."

The Vermont senator and self-described socialist then pivoted to highlight his 2020 campaign platform of breaking up the power wielded by Wall Street banks, as well as the fossil fuel and defense contracting industries. He also vowed to introduce reforms to make public college more affordable and minimize student debt.

Third Way, a Washington-based think tank that borrows its name from the centrist political theory, convened 250 people in Charleston this week for two days of speeches and panels after Sanders leaned into his socialist label and outlined his vision for a new "21st century economic bill of rights" during a speech at George Washington University earlier in June.

“He has made it his mission to either get the nomination or to remake the party in his image as a democratic socialist,” Third Way president Jon Cowan told the Guardian. “That is an existential threat to the future of the Democratic party for the next generation.”

Unlike the other candidates, who appeared onstage alone, Sanders sought to differentiate himself by making his remarks in front of people of color, including surrogates Rep. Ro Khanna, D-Calif., former Ohio state Sen. Nina Turner, and actor Danny Glover. He's been criticized for struggling to connect with black voters in the early-nominating state.

"We have a criminal justice system plagued by racism. We have seen an increase in hate crimes, including the horrific event at Emanuel AME church in Charleston," Sanders said, referring to the shooting of nine worshipers in 2015 by white supremacist Dylann Roof. "This is unacceptable and, as president, I will make it my priority to not only eliminate national economic disparities but racial disparities once and for all."