Senator Bernie Sanders apologized to Joseph R. Biden Jr. on Monday after a Sanders campaign surrogate wrote an opinion article accusing the former vice president of having “a big corruption problem.”
Mr. Sanders distanced himself from the piece by Zephyr Teachout, an associate professor at Fordham Law School, former New York political candidate and longtime supporter of Mr. Sanders. The op-ed, published on Monday in The Guardian, argued that Mr. Biden “represents the transactional, grossly corrupt culture in Washington that long precedes Trump.”
In an interview published Monday night, Mr. Sanders said he did not agree.
“It is absolutely not my view that Joe is corrupt in any way. And I’m sorry that that op-ed appeared,” Mr. Sanders told CBS News.
The Sanders campaign has recently intensified its attacks on Mr. Biden’s record, especially on Social Security, and the op-ed threatened to increase tensions between the Democratic candidates. Ron Klain, a top Biden adviser, said on Twitter before Mr. Sanders apologized: “There are a lot of legitimate issues to debate in 2020. But the only two campaigns ever to call @Joebiden “corrupt” are Trump and Sanders. What does that tell you?”
Later on Monday, Mr. Biden thanked Mr. Sanders for the apology.
“Thanks for acknowledging this, Bernie,” he said on Twitter. “These kinds of attacks have no place in this primary. Let’s all keep our focus on making Donald Trump a one-term president.”
The two were among the leading presidential candidates who joined arms on Monday in Columbia, S.C., to honor the Rev. Dr. Martin Luther King Jr., even as their campaigns tussled. Mr. Biden demanded an apology from Mr. Sanders for portraying him as open to cuts in Social Security, which he denies, but Mr. Sanders did not offer one.
On Saturday, Mr. Biden accused the Sanders campaign of using a “doctored” video to distort his record on Social Security. A Sanders adviser circulated a video on Jan. 1 that left out the context of Mr. Biden’s remarks but did not appear to be doctored.
Mr. Sanders campaigned for Ms. Teachout in her unsuccessful 2016 run in New York’s 19th Congressional District, helping to attract his avid supporters by appearing alongside her at campaign events. Ms. Teachout endorsed Mr. Sanders in his 2016 campaign against Hillary Clinton for the Democratic presidential nomination.
Ms. Teachout does not work for the Sanders campaign, but she has endorsed him.
In her opinion piece, she argued that nominating Mr. Biden would make it harder for Democrats to defeat President Trump.
“It looks like ‘Middle Class’ Joe has perfected the art of taking big contributions, then representing his corporate donors at the cost of middle- and working-class Americans,” Ms. Teachout wrote. “Converting campaign contributions into legislative favors and policy positions isn’t being ‘moderate.’ It is the kind of transactional politics Americans have come to loathe.”
Mr. Sanders told CBS News that he disapproved of his supporters demonizing political opponents online, saying “we need a serious debate in this country on issues.”
“I appeal to my supporters: Please, engage in civil discourse,” he said. “And by the way, we’re not the only campaign that does it. Other people act that way as well. I would appeal to everybody: Have a debate on the issues. We can disagree with each other without being disagreeable, without being hateful. That is not what American politics should be about.”