If Mr. Buttigieg is to win here Tuesday, he will have overcome not just Mr. Biden’s assault but also signs of political momentum for Ms. Klobuchar, who appeared to have gained some converts at her Saturday rallies following her confident debate performance. And the former mayor will also have to withstand direct attacks from Mr. Sanders, whose campaign has shifted its fire away from Mr. Biden and trained its sights on Mr. Buttigieg.
Addressing supporters in Dover, near New Hampshire’s coastline, before they went out for afternoon door-knocking, Mr. Sanders attacked Mr. Buttigieg by name.
“Billionaires by the dozen are contributing to Pete Buttigieg’s campaign,” said Mr. Sanders, who typically does not use his stump speech to lash his Democratic opponents.
“Now, I like Pete, he’s a smart guy, he’s a nice guy,” he continued. “But if we are serious about political change in America, that change is not going to be coming from somebody who gets a lot of money from the C.E.O.s of the pharmaceutical industry.”
But Mr. Buttigieg wasn’t the only more moderate Democrat Mr. Sanders took on in his remarks — he also invoked “the former mayor of New York” and suggested that Mr. Bloomberg is seeking “to buy an election” by pouring hundreds of millions of dollars from his personal fortune into the race.
Mr. Bloomberg, though, was far from the snowy New Hampshire campaign trail. He is not contesting the traditional early states.
While Mr. Sanders was deriding his self-funding, Mr. Bloomberg was in Washington addressing Democratic governors, a constituency that has been watching the party’s increasingly heated primary with growing despair.
Ms. Warren, for her part, did not dwell on rivals on Saturday, focusing instead on encouraging her supporters to turn out to vote on Tuesday and help her achieve a stronger showing than her third-place finish in Iowa.
Thomas Kaplan contributed reporting from Manchester, N.H., and Nick Corasaniti from Hanover.