Democrats worry that ongoing feud between Clinton and Sanders could ruin the party's chance at the presidency

Some Democrats are reportedly worried that ongoing infighting within their party between Bernie Sanders and his supporters and Hillary Clinton and the Democratic establishment could hurt their chances of winning the White House in 2020.

What infighting?

After her 2016 loss to President Donald Trump, Clinton blamed Sanders in her book "What Happened." She accused his "Bernie Bros" supporters of "harassing" her supporters online, and said that Sanders himself "had to resort to innuendo and impugning" her character because, according to Clinton, he couldn't debate her on policy issues.

"He didn't get into the race to make sure a Democrat won the White House," she wrote. "He got in to disrupt the Democratic Party."

Sanders supporters, meanwhile, accused the Democratic Party's use of superdelegates of unfairly giving Clinton an edge during the primary. Superdelegates are not tied to a state and can vote for either candidate. In 2016, they voted for Clinton early on in the primary. While Clinton was also ahead of Sanders with non-superdelegate delegates (2,205 to 1,983), Sanders supporters argued that the early support of the superdelegates gave Clinton a boost during the campaign.

The fighting has continued into this election cycle. Clinton has indicated that she will not be running in 2020, while Sanders has already launched his campaign and was able to raise $6 million during the first 24 hours after he announced.

In a February interview with Politico, former Clinton campaign director for rapid response, Zac Petkanas, mocked "his Royal Majesty King Bernie Sanders" who would "only deign to leave his plush D.C. office or his brand new second home on the lake if he was flown around on a cushy private jet like a billionaire master of the universe."

A spokesman for Sanders's 2016 bid dismissed this as "petty sniping" and called Clinton's team "some of the biggest a-holes in American politics."

What happened now?

Some Democrats, who hope to find a candidate who can unseat Trump next year, have had enough of the fighting between the two camps.

"I think there's a small segment of people in both camps who harbor significant resentment," Fox News quoted a "veteran New Hampshire-based Democratic campaign strategist" as saying. "There are Bernie people who have constantly attacked Clinton and there are Clinton people who resent the primary of 2016. I think this is a lingering problem that's going to find its way into the 2020 nomination process."

A member of the Democratic National Committee from New Hampshire, Kathy Sullivan, told Fox News that she thought people in both camps needed to "move on."

"The 2016 primary was three years ago…. We have another election coming up and that's what we should be focusing on," she said.

Former state Sen. Burt Cohen, who was part of Sanders' steering committee in New Hampshire, said that he thought the Clinton camp should learn from their loss, and help move the party to victory in 2020.

"We have to keep our eyes on the prize, which is saving America from Trumpism," he told Fox News "Carrying forth 2016 bitterness does no good."