Joseph R. Biden Jr. unfurled sharply personal new lines of attack against Senator Elizabeth Warren on Tuesday, questioning her contributions to the Democratic Party and seeking to cast her as an elitist who believes people lack courage or wisdom unless they agree with her.
“Some call it the ‘my way or the highway’ approach to politics,” Mr. Biden, the former vice president, wrote in a Medium post. “But it’s worse than that. It’s condescending to the millions of Democrats who have a different view. It’s representative of an elitism that working and middle-class people do not share: ‘We know best; you know nothing.’ ‘If you were only as smart as I am you would agree with me.’ This is no way to get anything done.”
Mr. Biden repeated similar arguments in a fund-raising email and at a fund-raiser in Pittsburgh on Tuesday, escalating tensions between the two top-polling contenders for the Democratic presidential nomination. He did not mention his rival by name, but the message was unmistakably aimed at Ms. Warren, whose Republican critics have for years sought to paint her as an out-of-touch liberal who worked as a Harvard professor.
Ms. Warren is running as a corruption-battling economic populist, and her campaign has emphasized that she grew up in Oklahoma “on the ragged edge of the middle-class.” Her campaign declined to comment on Mr. Biden’s remarks.
Mr. Biden and Ms. Warren have clashed repeatedly over health care, especially as Ms. Warren has overtaken Mr. Biden in some early-state polls. Ms. Warren supports “Medicare for all,” an expansive government-run health insurance system that would all but eliminate private health insurance, while Mr. Biden wants to add a “public option” to build on the Affordable Care Act, but still allow people to choose private insurance.
Last week, after Mr. Biden’s campaign criticized Ms. Warren’s proposal to pay for Medicare for all, she suggested that Mr. Biden was “running in the wrong presidential primary.”
“Democrats are not going to win by repeating Republican talking points and by dusting off the points of view of the giant insurance companies and the giant drug companies who don’t want to see any change in the law that will bite into their profit,” she said.
Her message drew a pointed rebuke from Mr. Biden, who wrote that such remarks “reflect an angry unyielding viewpoint that has crept into our politics. If someone doesn’t agree with you — it’s not just that you disagree — that person must be a coward or corrupt or a small thinker.”
Some of Ms. Warren’s other opponents, including Senator Amy Klobuchar of Minnesota and Mayor Pete Buttigieg of South Bend, Ind., have also been critical of Ms. Warren’s health care proposal, and of her approach to promoting it.
In several venues on Tuesday, Mr. Biden also repeatedly seized on the fact that Ms. Warren was once a registered Republican, though she is now a leading progressive contender for the Democratic nomination and Mr. Biden is perceived by many on the left as too moderate and overly focused on striking deals with Republicans.
“I have fought for the Democratic Party my whole career,” Mr. Biden wrote. “I know what we stand for, who we stand with and what we believe. And it’s not just policies or issues. It’s in my bones. That’s not something everyone in this primary can say.”
He was more explicit at the fund-raiser: “I’ve been a Democrat my whole life. This person has only fairly recently in the mid-’90s become a Democrat.”
Ms. Warren’s team has in the past been critical of Mr. Biden’s reliance on high-dollar fund-raising events.
Mr. Biden and his allies often bristle at the suggestion that he is insufficiently progressive for this moment in the Democratic Party, and Mr. Biden on Tuesday sought to defend his liberal credentials on issues like health care and taxes.
But his use of personal criticisms to confront Ms. Warren, the only woman polling in the top tier of Democratic contenders, carries risk. Attacks on character, including on Mr. Biden’s, have often failed to land or have backfired in the primary process so far.
Mr. Biden cast his remarks as self-defense.
“Since some have questioned whether I’m running in the wrong primary — let me answer that question,” he continued. “I’m running in the Democratic primary as a proud Democrat.”