DES MOINES, Iowa – On the eve of the Iowa caucuses, Sen. Bernie Sanders predicted that the first contest in the race for the Democratic presidential nomination will lead to the end of President Trump’s tenure in the White House.

“Tomorrow night is the beginning. It is the beginning of the end for Donald Trump,” the independent senator from Vermont, who is making his second straight presidential bid, told cheering supporters at a sports pub in Iowa’s capital city.

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And the populist lawmaker once again spotlighted that turnout will be crucial to his success in the caucuses.

“Tomorrow night please do your best not only to come out and caucus, bring your friends, bring your distant cousins, bring those people you haven’t talked to in years, and get them out to the caucus,” the candidate joked as he urged his supporters to convince friends and family to caucus on his behalf.

And Sanders -- speaking Sunday what was billed as a Super Bowl watch party -- repeated his prediction that “if the turnout tomorrow night is low, we’re going to lose. If the turnout is high, we’re going win. Our job together is to create the highest turnout in the history of the Iowa caucus.”

An average of the latest polls in Iowa’s Democratic presidential caucuses compiled by RealClearPolitics indicates Sanders with a low single-digit edge over former Vice President Joe Biden, with former South Bend, Indiana Mayor Pete Buttigieg and Sen. Elizabeth Warren of Massachusetts a few percentage points back, and Sen. Amy Klobuchar of neighboring Minnesota hovering just below double digits.

Warren also wrapped up her final day on the campaign trail in Iowa at a Super Bowl watch party. The senator arrived at the event, which was hosted by Progress Iowa, carrying a six-pack of beer.

She told the crowd that “you, Iowa, have made me a better candidate, and you will make me a better president.”

Earlier, at a town hall in Iowa State University in Ames, Warren once again emphasized that choosing a female nominee is the best way to defeat the GOP president in November’s general election.

“Right now across in America in competitive races, women are outperforming men. So here' how I see this -- our number one job is to beat Donald Trump. Women win,” she stressed.

Klobuchar joined her fellow senators in ending her day at Super Bowl watch party at Jethro’s BBQ N’ Pork Shop Grill in suburban Des Moines.

A strong finish in Iowa’s caucuses is crucial for Klobuchar’s uphill climb to win the Democratic presidential nomination. And some political pundits have spotlighted that a less than stellar showing in Monday night’s caucuses could spell doom for Klobuchar.

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But in an exclusive interview Sunday on "Fox News Sunday," the Democratic White House hopeful vowed that “I’m going to New Hampshire no matter what.”

New Hampshire votes eight days after Iowa and holds the first primary in the race for the presidential nominations.

All three senators returned to the nation’s capital on Sunday night in order to attend Monday’s session of the Senate impeachment trial of President. And all three hope to return to Iowa on Monday evening in time for the caucuses.

Buttigieg -- pointing to then-Sen. Barack Obama’s historic victory in the 2008 Iowa caucuses -- asked his supporters at a large rally in Des Moines on Sunday to repeat history.

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Buttigieg -- who would become the nation’s first openly gay president if elected -- asked “are you ready to make history one more time tomorrow evening. And make sure that everybody has a voice in this process. I believe you're going to make me the next president to the United States.”

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Biden wrapped his final day of campaigning ahead of the caucuses by addressing his largest crowd to date in Iowa. Just over 1,100 people showed up to see the former vice president Sunday evening at a middle school on the east side of Des Moines.

Fox News' Andrew Craft, Tara Prindiville, Allie Raffa, Andres del Aguila, and Mitti Hicks contributed to this report