Just one day before the New Hampshire Democratic primary, U.S. Sen. Bernie Sanders has the lead among those vying for the party’s nomination, but 40% of likely voters say they could still change their mind, according to a new poll released Monday by the UMass Lowell Center for Public Opinion.

Sanders is leading by eight points, with the support of 25% of likely voters in the Democratic primary. Sanders, who won the 2016 New Hampshire Democratic primary, is up 2% in today’s poll over the results of the poll issued Feb. 3 by the UMass Lowell Center for Public Opinion.

The nonpartisan poll of 440 likely New Hampshire Democratic primary voters was independently funded by the University of Massachusetts Lowell. The survey was designed and analyzed by the Center for Public Opinion and fielded by YouGov from Feb. 4 through Feb. 7. It has a margin of error of plus or minus 6.5%.

Channel 2's Jorge Estevez shows you the latest polling in New Hampshire before the primary debate.

A week ago, Sanders was in a race too close to call with former Vice President Joe Biden and U.S. Sen. Elizabeth Warren, as all three were within four points of each other and the margin of error of the Feb. 3 poll. As of Monday's poll, Sanders has expanded his lead and is solidly in first place.

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Mayor Pete Buttigieg has vaulted past Biden and Warren into second place, with 17%, up five points since a week ago. Biden, who was just a point behind Sanders Feb. 3 with 22%, has dropped eight points into fourth place with 14%. Warren is in third place, but is down from 19% to 15%.

“We are now looking at a race with a leader. After the chaos surrounding the Iowa caucus, Sanders has emerged as the candidate to beat in a state he won by more than 20 points in 2016. But Buttigieg is on the rise and received the biggest post-Iowa bump,” said Joshua Dyck, director of the Center for Public Opinion and an associate professor of political science.

Pete Buttigieg spent Sunday on defense as his Democratic presidential rivals attacked him on everything from his struggle to connect with black voters to accepting campaign contributions from large donors in an effort to blunt any momentum heading into Tuesday's New Hampshire primary.

“With Joe Biden and Elizabeth Warren trending downward, the question is, does Mayor Pete have enough time and can he woo enough of the soft support away from other candidates to catch Bernie?”

U.S. Sen. Amy Klobuchar, who was tied last week with businessman Tom Steyer, has climbed two points to 8% to hold fifth place on her own. Steyer has dropped 1 point since last week to 5%. U.S. Rep. Tulsi Gabbard is down 1 point to 4%, businessman Andrew Yang is up 1 point to 3% and former Massachusetts Gov. Deval Patrick remains at 1%.

Massachusetts Sen. Elizabeth Warren was out on the campaign trail in Keene, New Hampshire on Tuesday, telling her story to voters during the last push before New Hampshire's primary.

Among women polled, Sanders has the most support, with 29%, followed by Warren with 17%, Buttigieg with 14% and Biden with 9%. Sanders’ support with women likely primary voters is stronger than among men who are likely voters, 20% of whom said they support him, behind Biden and Buttigieg, both of whom garnered 21%, and Warren at 12%.

Even with the shifts in support for candidates over the last week and Sanders solidifying his lead, four in 10 likely Democratic primary voters still say they could change their mind and vote for a different candidate, virtually no change since the Feb. 3 poll.

As the nation's first primary approaches, New Hampshire officials are working to ensure things go a lot more smoothly than they did in Iowa on Monday.

“Normally, electorates grow in certainty as the election nears, but both the percentage of those who said they could change their mind and that there is no change since a week ago suggests a high degree of instability for an election that will take place in one day. New Hampshire primary voters appear to be living up to their reputation of waiting until the very end to decide,” said Dyck.

Sanders’ base of likely voters who support him remains the most stable, with 87% (a one-point change from Feb. 3) saying they will definitely vote for him and only 13% saying that they could change their mind. Among Buttigieg voters, 53% (down from 71% a week ago) say they could still change their mind, while 42% of Biden voters (up 10%) and 41% of Warren voters (up 3%) say they could vote for another candidate. Nearly two-thirds, 65% (up from 58% a week ago), of Klobuchar voters also say that they could still change their mind.

Sanders stumps in New Hampshire ahead of state's primary

Likely Democratic primary voters changed their minds over the last week about who they think will win the party’s presidential nomination. Sanders now leads with 30%, up six points over a week ago. The percentage of likely voters who think Biden will get the nomination has dropped 19 points since Feb. 3 from 42% to 23%. Buttigieg has gained nine points, going from 3% to 12%, while Warren has dropped to 7% (down one point). No other candidate received higher than 2%.

The survey found that 41% of likely voters feel Biden would best continue the legacy of former President Barack Obama; Buttigieg is in a distant second at 13%. Forty-four percent said they think Obama – who has an 86% favorability rating among those polled – would support Biden in a primary, but 65% said they feel Obama should not endorse a presidential candidate.

“Joe Biden has been running from Day 1 as Barack Obama’s successor and someone who can beat Trump. While New Hampshire Democratic primary voters view Biden positively and associate him with Obama, Biden has lost their confidence that he can win the nomination and beat Trump in a general election. The fundamentals are still there for Joe Biden, but his campaign can’t, to borrow a Trumpism, seem to close the deal. To these voters, Biden just doesn't look like a winner,” said John Cluverius, associate director of the Center for Public Opinion and assistant professor of political science.

Given the high degree of polarization in the country and the competitiveness of elections, supporting political candidates can sometimes strain personal relationships. Thirty percent polled reported their attitudes about Trump had strained relationships, but only a small percentage said so about their support for a Democratic candidate.

“There are some potentially good signs in this poll for Democrats concerned about whether the party will be able to unify. Very few voters, only 3%, report that supporting a candidate in the Democratic nominating contests has caused strained relationships for them with friends or family. This is a good reminder that some of the intra-party fighting that plays out on social media platforms like Twitter is not real life,” said Dyck.