State Senator Martha Fuller Clark was the only one of New Hampshire's eight superdelegates to support Sen. Bernie Sanders.
That's despite Sanders' 22-point victory in in the state in February.
She cast her vote during Tuesday night's roll call at the Democratic National Convention in Philadelphia.
But now that Hillary Clinton is officially the Democratic nominee and Sanders has endorsed her, Fuller Clark says it's time for all Democrats to rally behind the former Secretary of State.
"They’re really taking a risk of putting the presidency in jeopardy," Fuller Clark told NHPR's Morning Edition, referring to the so-called "Bernie or Bust" movement.
"We’ve heard over and over again over the last 24 to 48 hours that this really is the most important election in our lives. Democracy and the Supreme Court are at stake," she added. "It’s fine to stand on principle, but also politics is the art of the possible and I would hope they would understand the seriousness of this campaign."
Many Sanders delegates staged a walk-out Tuesday night after Clinton clinched the nomination. Many say they'll either sit out the election or vote for a third-party candidate.
Fuller Clark, who's now backing Clinton, says Sanders supporters should recognize the way his campaign was ultimately able to pull Clinton to the left on issues like the minimum wage and college affordability.
"A lot of her positions have been modified and she’s now embracing the principles and goals of the Sanders campaign," she said. "That’s why Sanders delegates and supporters feel that this is such a victory."
But she says all of that will be lost if Donald Trump, the Republican nominee, is elected president.
You can find the full transcript of her interview below:
Looking back to Tuesday night’s roll call: why was it so important for you and other Sanders supporters to be able to cast your votes for him?
Because it’s important that the voters of New Hampshire feel that their vote counted. And you will remember that we overwhelmingly in the primary as a state voted for Bernie Sanders. To recognize that was important to each and every delegate that was pledged to Bernie Sanders.
You were the only superdelegate from New Hampshire to support Sanders, despite the fact that he won the state by more than 20 points. Does the superdelegate system need to be changed?
Well, we do know that as part of the platform that a commission has been set up to look at what the role of the superdelegates should be. And I know that we have three, almost four years to work that out in a way that I believe that we’ll have a better opportunity to bring all Democrats together and make them feel that their vote counts.
You’ve said you’ll now back Hillary Clinton in the election, but Sanders raised some real concerns about her during the primary: he criticized her ties to Wall Street and called into question her judgement at times.
How do you move past those differences?
I think it’s important to understand that it’s thanks to Senator Sanders and his supporters that we’ve been able to bring Secretary Clinton along. A lot of her positions have been modified and she’s now embracing the principles and goals of the Sanders campaign. That’s why Sanders delegates and supporters feel that this is such a victory. And having Senator Sanders and having Elizabeth Warren still in the Senate will make sure that these objectives are acknowledged and worked going forward over the next four years.
Do you think the so-called Bernie or Busters are being unrealistic by saying they’ll sit out the election?
I think they’re being not only unrealistic, but they’re really taking a risk of putting the presidency in jeopardy. We’ve heard over and over again over the last 24 to 48 hours that this really is the most important election in our lives. Democracy and the Supreme Court are at stake. It’s find to stand on principle, but also politics is the art of the possible and I would hope they would understand the seriousness of this campaign and that they would join us, particularly now that the platform includes so many of their goals and objectives.
We saw the revelation this week regarding the leaked emails from the Democratic National Committee showing officials appeared to be biased toward Clinton during the primary.
Has that made it harder for you to move on?
I think it would be important to underline that when you say officials, we’re really talking about the chair of the DNC (Debbie Wasserman Schultz) and her staff. Yesterday, the executive committee of the DNC said they were not aware of what was going on. They have apologized to Bernie Sanders. They are committed to making sure that this never happens again and we need to go forward. We have a lot to do to rebuild the credibility of the DNC. But there are many honorable individuals who represent this party and I know that they’re going to make sure going forward, we’re more transparent and clearly remain objective in our support. That’s why I chose to remain neutral in the primary in New Hampshire until after the primary was over and the delegates had been chosen. It’s important that we as officers remain neutral.
Hillary Clinton is set to speak tomorrow night. What are you hoping to hear from her?
We had the most remarkable speech last night from President Clinton. He really told a story about Hillary Clinton and who she is. It was very moving and I’m hoping that tomorrow night that she will embrace in her presentation and words and gestures all that she can be as President of the United States. It’s really quite extraordinary that we now have a woman nominee and I believe she will be an extraordinary president. It’s our job to get her elected.