DES MOINES — Pete Buttigieg continues to surge in Iowa, leapfrogging Senator Elizabeth Warren and former Vice President Joseph R. Biden Jr. to hold a commanding lead among likely Democratic caucusgoers, according to a new poll from The Des Moines Register and CNN.
The poll showed that Mr. Buttigieg was the first choice for 25 percent of would-be Democratic caucusgoers, a significant increase from the 9 percent he held in September, when The Register last polled the state. The support placed him far ahead of the rest of the field — with the other three top candidates in a virtual tie for second: Ms. Warren, at 16 percent and Mr. Biden and Senator Bernie Sanders at 15 percent.
The results are the latest evidence of Mr. Buttigieg’s strength in Iowa, where his moderate political views, plain-spoken style and military history have resonated in the early voting state. He placed fourth in the state in September.
It also suggests that voters, in Iowa at least, are increasingly favoring a centrist agenda — a view that has drawn two new entrants, Deval Patrick, the former governor of Massachusetts, and Michael R. Bloomberg, the former mayor of New York City, — into the race this month.
The poll results reflect the deep split within the Democratic Party over whether it is veering too far to the left to defeat President Trump. Speaking on Friday to a room of wealthy liberal donors, former President Barack Obama expressed concern about some of the policy ideas being promoted by some of the candidates, citing health care and immigration as issues where the proposals may not align with public opinion.
Though he did not name any candidates directly, his remarks were seen as an implicit criticism of Mr. Sanders and Ms. Warren, two of the leading candidates who are pushing policy plans once considered too liberal, like “Medicare for all,” with the broader goal of “political revolution” and “big, structural change.”
“Even as we push the envelope and we are bold in our vision we also have to be rooted in reality,” Mr. Obama said. “The average American doesn’t think we have to completely tear down the system and remake it.”