Sen. Bernie Sanders said Sunday that the Iowa caucuses marked the “beginning of the end for Donald Trump.”

It would be the "moment when we tell the billionaire class in the 1 percent: this country belongs to all of us, not just a few," he told a crowd at a Super Bowl party.

In most polling, the Vermont senator is at the top of the race in the state.

The latest Emerson College poll, which came out Sunday night, for example, shows the Democratic socialist leading the field with 28 percent support in the state, while former Vice President Joe Biden follows him with 21 percent support of likely caucusgoers.

He also took his case to Twitter.

"By joining our movement, you're joining a fight for human solidarity," he said. "You're standing against all forms of racism, bigotry and discrimination. You're working towards criminal justice reform, a humane immigration system and disability rights. That’s what this campaign is about."

By joining our movement, you're joining a fight for human solidarity.



You're standing against all forms of racism, bigotry and discrimination.



You're working towards criminal justice reform, a humane immigration system and disability rights.



That's what this campaign is about. — Bernie Sanders (@BernieSanders) February 3, 2020

The prospect of Sanders winning the party nomination has reportedly become a big concern among some Democrats, including former Secretary of State John Kerry who is in the state as a Biden surrogate.

Former Secretary of State John Kerry — one of Joe Biden's highest-profile endorsers — was overheard Sunday on the phone at a Des Moines hotel explaining what he would have to do to enter the presidential race amid "the possibility of Bernie Sanders taking down the Democratic Party — down whole." Sitting in the lobby restaurant of the Renaissance Savery hotel, Kerry was overheard by an NBC News analyst saying "maybe I'm f---ing deluding myself here" and explaining that to run, he'd have to step down from the board of Bank of America and give up his ability to make paid speeches. Kerry said donors like venture capitalist Doug Hickey would have to "raise a couple of million," adding that such donors "now have the reality of Bernie."

Kerry later denied wanting to run for president in a (now deleted) tweet that dropped an f-bomb.

"This is a complete and total misinterpretation based on overhearing only one side of a phone conversation," he told NBC. "A friend who watches too much cable called me wondering whether I'd ever jump into the race late in the game if Democrats were choosing an unelectable nominee. I listed all the reasons I could not possibly do that and would not — and will not under any circumstances — do that."