“Unlike some of the campaigns up here,” Mr. Sanders said, “I don’t have 40 billionaires, Pete, contributing to my campaign.”
Even Andrew Yang, the former tech entrepreneur who has rarely used his debate appearances to target his rivals, saw an opportunity to take on Mr. Buttigieg. “Pete, fundamentally, you are missing the lesson of Donald Trump’s victory,” Mr. Yang said after Mr. Buttigieg denounced the Trump presidency. “Donald Trump is the not the cause of all of our problems. And we are making a mistake when we act like he is.”
But like Mr. Sanders himself, in the moments when he was under attack, Mr. Buttigieg gave no ground, arguing determinedly for his own distinctive approach to the 2020 race. He batted away skepticism of his lack of service in the highest levels of government and rejected Mr. Sanders’s demand for purity in political fund-raising. The Trump campaign would be coming at the eventual Democratic nominee with an immense war chest, Mr. Buttigieg said, arguing that “we need to go into that fight with everything that we’ve got.”
And in a sign of his confidence in his positioning as a Washington outsider, Mr. Buttigieg conceded the point on his lack of traditional qualifications for the presidency, seeming to imply that voters who were looking for a candidate with that profile already had an option in Mr. Biden.
“I freely admit that if you’re looking for the person with the most years of Washington establishment experience under their belt,” Mr. Buttigieg said, “then you’ve got your candidate and of course it’s not me.”
He countered criticism from Mr. Biden and Ms. Klobuchar, who accused him of minimizing his party’s work in Washington, by respectfully relegating those accomplishments to the past. “Those achievements were phenomenally important because they met the moment,” Mr. Buttigieg said. “But now we have to meet this moment, and this moment is different.”
The flurry of attacks and reprisals was unsurprising so close to the primary here, and with polls showing the two top-performing Iowa candidates also leading in New Hampshire. What was striking, though, was that, after finishing in a distant third in Iowa, Ms. Warren recited her familiar attacks on corruption and largely shied away from confronting her rivals. Even when given the chance to take on Mr. Sanders and Mr. Buttigieg, she offered only the most glancing critiques before returning to her broader message.