MANCHESTER, N.H. – With three weeks to go until the first primary in the race for the White House, a new poll indicates that the battle for the Democratic presidential nomination is wide open in New Hampshire.

According to the Suffolk University survey for the Boston Globe, Sen. Bernie Sanders of Vermont and former Vice President Joe Biden top the field.

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But nearly a quarter of likely Democratic primary voters questioned in the survey -- which was released Tuesday -- say they’re undecided. And nearly half say they might change their mind on whom they’re backing before the Feb. 11th primary.

The survey spotlights the uncertainly in the still large field of Democratic White House hopefuls and New Hampshire’s tradition of being late-deciding voters.

"Granite State voters are fickle and have surprised us all in the past," noted pollster David Paleologos, director of the Suffolk University Political Research Center.

"They not only want to shake the hands of candidates, they want to hold their feet to the fire until the very last minute almost as a service to the rest of the country by judging candidates when the pressure is most intense mere days before the primary," he added.

Sanders, the populist lawmaker from Vermont who's making his second straight White House bid, stands at 16 percent among likely Democratic primary voters, with the former vice president at 15 percent. Sanders’ 1 percentage point edge is well within the survey’s sampling error.

For 100 years, New Hampshire has held the first primary in the race for the White House. A sign marking the primary's history stands outside the Statehouse in Concord, NH

Former South Bend, Indiana Mayor Pete Buttigieg’s at 12 percent, with Sen. Elizabeth Warren of Massachusetts at 10 percent, and tech entrepreneur Andrew Yang at 6 percent. Rep. Tulsi Gabbard of Hawaii, who’s spending most of her time campaigning in the Granite State, is at 5 percent, as is Sen. Amy Klobuchar of Minnesota. Billionaire environmental and progressive advocate Tom Steyer’s at 3 percent, with everyone else sampled in the poll at 1 percent or less.

Sanders stands at 19.8 percent in the latest Real Clear Politics average of the four public opinion surveys conducted in New Hampshire this month, with Biden at 18.5 percent, Buttigieg and Warren each at 14.3 percent and everyone else in single digits.

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Sanders and Warren each live in neighboring states to New Hampshire, and Sanders crushed eventual nominee Hillary Clinton in the 2016 Democratic presidential primary in the Granite State, which was essentially a two-candidate race.

The Suffolk University poll for the Boston Globe was conducted Jan. 15-19, with 500 likely Democratic primary voters in New Hampshire questioned by live telephone operators. The survey’s sampling error is plus or minus 4.4 percentage points.