With solid support from liberals, Mr. Sanders appears to be peaking just as the caucuses approach. But many Iowa voters said they could still change their mind.
DES MOINES — Senator Bernie Sanders has opened up a lead in Iowa just over a week before the Democratic caucuses, consolidating support from liberals and benefiting from divisions among more moderate presidential candidates who are clustered behind him, according to a New York Times/Siena College poll of likely caucusgoers.
Mr. Sanders has gained six points since the last Times-Siena survey, in late October, and is now capturing 25 percent of the vote in Iowa. Pete Buttigieg, the former mayor of South Bend, Ind., and former Vice President Joseph R. Biden Jr. have remained stagnant since the fall, with Mr. Buttigieg capturing 18 percent and Mr. Biden 17 percent.
The rise of Mr. Sanders has come at the expense of his fellow progressive, Senator Elizabeth Warren: she dropped from 22 percent in the October poll, enough to lead the field, to 15 percent in this survey. Senator Amy Klobuchar, who is garnering 8 percent, is the only other candidate approaching double digits.
The changing fortunes of the two liberal candidates, and the secondary position of the two leading centrists, underscores the volatile nature of the Democratic primary after more than a year of campaigning, as voters wrestle with which of the contenders can defeat President Trump. At various times over the past six months Ms. Warren and Mr. Buttigieg had surged in Iowa, only to fall back, while Mr. Biden’s strength has ebbed and flowed here even as he remained at the top of the polls nationally.
Despite Mr. Sanders’s ascent, the combined strength of the moderate candidates is unmistakable. The poll showed that 55 percent of those surveyed said they preferred a standard-bearer who is “more moderate than most Democrats.” Just 38 percent said they wanted one who is “more liberal than most Democrats.”
A victory by Mr. Sanders in Iowa, where he suffered a narrow loss to Hillary Clinton four years ago, would represent a remarkable comeback for a 78-year-old candidate whose heart attack in October threatened to upend his candidacy. It would also create a moment of high anxiety for establishment-aligned Democrats who are deeply alarmed about a potential Sanders nomination.
“Bernie’s authentic,” said Austin Sturch, 25, of Evansdale, adding, “Pretty much everything he’s saying — I can’t put it better than he can.”
Still, much here remains uncertain. Iowa voters are famous for settling on a candidate late, and this year is no different; Mr. Sanders, along with the other senators in the race, is pinned down in Washington during Mr. Trump’s impeachment trial and unable to campaign here on weekdays. And the final results could turn on two factors that will not be known until caucus night: the size and composition of the electorate, and the preferences of voters whose first choices are eliminated because of the arcane caucus rules. SOURCE