Her comments following a town hall here came after POLITICO reported on Saturday that Sanders’ campaign had developed a script instructing volunteers to criticize Warren as appealing to “highly-educated, more affluent people” and say that she was “bringing no new bases into the Democratic Party.” It was a breach of the quasi non-aggression pact between the two progressive senators, who have been longtime friends and ideological allies and have largely refrained from hitting each other during the presidential primary.

“I was disappointed to hear that Bernie is sending his volunteers out to trash me,” Warren said. “Bernie knows me, and has known me for a long time. He knows who I am, where I come from, what I have worked on and fought for, and the coalition and grass-roots movement we’re trying to build.”

Sen. Bernie Sanders. | Scott Olson/Getty Images

Speaking at an event in Iowa City, Sanders distanced himself from the talking points produced by his campaign and maintained that he did not personally approve them. He seemed to attribute the script, which read “PAID FOR BY BERNIE 2020,” to a rogue employee.

“We have hundreds of employees. Elizabeth Warren has hundreds of employees. And people sometimes say things that they shouldn’t,” Sanders said, adding that Warren is “a friend of mine” and that “[n]o one is going to be attacking Elizabeth.”

Not everyone on Sanders’ campaign staff fell in line, however. The national press secretary, Briahna Joy Gray, tweeted on Sunday afternoon : “Warren has plenty to recommend her, but nominating the candidate who people don’t feel so strongly abt 1 way or the other is not how you beat a man as galvanizing as Trump.”

Julián Castro, who dropped out of the Democratic race earlier this month and recently endorsed Warren and introduced her at the town hall here, told POLITICO he was “disappointed that Bernie would go negative on somebody that he’s known for a long time, and worked with, and whose character he must certainly know is good.”

Warren used the Sanders campaign memo to try to further her pitch as a progressive candidate who will build bridges and lead a united party into the general election — a pitch that is also meant to address voter concerns about her electability.

“We cannot nominate someone who takes big chunks of the Democratic coalition for granted,” Warren said after referring to the division of 2016. “We need someone who will bring our party together.”

Sanders and his inner circle have long bristled at the idea that his campaign against Clinton contributed to her defeat, often referencing his many stops on the trail for her in the fall of 2016.

The escalating tensions come just weeks before the Iowa caucuses, in which Sanders is narrowly ahead of Warren — 20 percent to her 17 percent, according to the latest Des Moines Register poll. The poll put Sanders in first place for the first time in the Hawkeye State. Sanders has resurged after his heart attack last fall, reconsolidating many supporters on the left who seemed to be considering Warren and easily besting all of his rivals in fundraising.

Weekly Score Your guide to the year-round campaign cycle. Sign Up Loading By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

With that, however, has come renewed scrutiny and a brighter spotlight than before.

His campaign appears ready to press the attack in the final weeks. He escalated offensives against both former Vice President Joe Biden and Mayor Pete Buttigieg of South Bend, Ind., in addition to the new jabs at Warren in the script.

“The problem is, no one is really excited about him,” the script said of Biden. “He doesn’t really have any volunteers and has no support at all among young people.”

