Sen. Bernie Sanders on Sunday dismissed claims from some Democrats that it would be difficult to unite the party around him, insisting on ABC's "This Week" that the "threat" that President Trump poses will rally Democratic voters and leaders to support the eventual nominee.

What he's saying: "At the end of the day, I have known Joe Biden for a very long time. He is a decent guy. I have no doubt that if I win, Joe will be there. If Joe ends up winning, I will be there. We are going to come together and President Obama in my view — he has said this — will play a leading role in helping whoever the Democratic nominee is."

Why it matters: Establishment Democrats have been sounding the alarm over nominating a democratic socialist, believing that Sanders will lose to President Trump in the general election and damage down-ballot candidates for House and Senate.

Sanders supporters, many of whom adopted the mantra "Bernie or bust" in 2016, are also the least likely of any candidate's base to say they'll support the eventual Democratic nominee if it isn't Sanders, according to polling.

Trump has been stoking these flames as well, persistently tweeting about whether the Democratic Party will "steal" the nomination from Sanders. Trump advisers told Axios they want to promote the rise of Sanders, believing he will be an easy candidate to defeat.

The big picture: While Sanders still leads the pack as the Democratic front-runner heading into Super Tuesday, Joe Biden's sweeping victory in South Carolina Saturday night could give him a much-needed boost of momentum.