Democratic presidential contender Bernie Sanders holds a strong lead in Iowa over a week before the caucus in the state, according to a New York Times/Siena College poll.
The senator from Vermont's support has swelled by six points since the last Times-Siena survey in late October, and he's now garnering 25% of the Iowa vote.
Support for the more moderate candidates -- Pete Buttigieg, the former mayor of South Bend, Ind., and former Vice President Joe Biden -- has stalled since the fall. Buttigieg has 18% of the vote and Biden 17%.
Progressive voters are rallying behind Sanders more than his opponent on the left Sen. Elizabeth Warren, whose support in Iowa has waned to 15% from 22% in the the last Times-Siena survey. At that point, Warren was leading the pack of Democratic presidential candidates.
Sanders, a democratic socialist making a second run for the presidency, also showed a lead in a poll earlier this month from The Des Moines Register and CNN.
If Sanders won Iowa, his campaign would likely see fresh momentum and support going into New Hampshire, Nevada and South Carolina. The 78-year-old candidate narrowly lost Iowa to Hillary Clinton four years ago.
Yet the outcome is far from certain, with voters in Iowa famous for unpredictability. Indeed, some 40% of voters say they could still caucus for another candidate, the New York Times/Siena College poll found.