Photo: Todd Heisler/The New York Times; Video: By THE ASSOCIATED PRESS

Senator Bernie Sanders of Vermont sought to temper expectations by stressing that losing the caucus to Hillary Clinton would not be “the end of the world.”

Standing outside his campaign headquarters in Des Moines, Mr. Sanders played down the importance of Iowa, a majority white and liberal-leaning state that seems tailor made for the senator’s grass-roots style of campaigning and his progressive call for a political revolution led by the working class.

“We have state after state after state,” Mr. Sanders said as he stood in the doorway of the campaign bus bearing his name. “This is a national campaign.

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“Look, we are looking forward to it. We want to win. We worked hard to win. But if she ends up with two delegates more — there are many, many hundreds of delegates — you tell me why that is the end of the world? I think she would say exactly the same thing. It’s a long process.”

Mr. Sanders and his campaign advisers also stressed that his campaign does not have a “super PAC” and that its average donor contributes $27. “We are seeing just today the reports that come in for super PACs,” Mr. Sanders said, “and guess what? Shock of all shocks — Wall Street is pouring huge amounts of money into Republican candidates and into Democratic candidates.”

Meanwhile, Mr. Sanders’s campaign raised $20 million in January, an enormous amount that backs up the campaign’s assertion that it will have enough money for a long, hard-fought nominating fight.

Mr. Sanders also said that he was proud of the campaign he ran in Iowa and that he was happy to not have more pointedly attacked Mrs. Clinton. “I think not doing ugly, negative ads is the right thing to do,” he said. “And you know what I think? It’s good politics.”

Before he talked about possibly losing, Mr. Sanders greeted volunteers inside his campaign headquarters. Just before he arrived, dozens of people sat at computers frantically making last-minute calls imploring people to vote for him. Others were quickly typing up names of Sanders supporters in an effort to increase his voter database. As Mr. Sanders walked in, the volunteers cheered “Bernie! Bernie! Bernie!”

In a short speech, Mr. Sanders said, as he had in the past, that a high voter turnout would mean a win for him and that a low voter turnout would be a “struggle.” The senator said as of Monday, he had spoken to about 70,000 people at more than 100 town-hall-style meetings across Iowa.

Once outside, Mr. Sanders told reporters he planned to continue campaigning until the Democratic National Convention this summer. “After we go to New Hampshire, we’re going to be in Nevada, then South Carolina, then dozens of other states around this country,” he said. “We are in this to win at the convention. We’re taking this all of the way.”