Bernie Sanders’ presidential campaign raised $33 million in the last quarter of 2015, providing him the resources to remain a formidable challenger to Hillary Clinton with less than a month left until the first ballots are cast in Iowa.

“This people-powered campaign is revolutionizing American politics,” Sanders’ campaign chief said Saturday in a statement.

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The self-proclaimed democratic socialist took in $73 million on the year, a figure most thought unimaginable when Sanders launched his dark horse candidacy in April. His campaign says it has about $28 million cash on hand.

Meanwhile, Clinton reported $37 million raised in the final quarter, bringing her total haul for the year to $112 million, with $38 million still in the bank.

Despite the apparent money edge Clinton has over her rival, Sanders’ fundraising haul assures that she won’t be able to deliver the knockout blow she has sought.

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After a turbulent summer where questions about Clinton’s use of a private email server while acting as Secretary of State washed away her veneer of inevitability and allowed Sanders to narrow the gap in the polls, the former First Lady has regained control of the race.

As a result, Clinton has increasingly turned her focus to the general election. She refused to be drawn into contentious arguments with Sanders during last month’s Democratic debate and has begun saving her best campaign barbs for Republican presidential frontrunner Donald Trump, who has accused her of exploiting women while calling former President Bill Clinton “one of the great women abusers of all time.”

Sanders’ fundraising means he will be able to maintain his elaborate ground operation in Iowa. The New York Times reports that he has organizers sprinkled liberally throughout the Hawkeye State who will work to turn out the vote on Feb. 1.

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Clinton leads in the most recent Iowa polls, but a surprise win or better-than-expected showing by Sanders could spark a fresh round of donations from liberal Democrats ahead of the Feb. 20 New Hampshire primary, where Sanders has the edge in the polls.

A win in the Granite State would keep the river of fundraising flowing and threaten to drag the Democratic primary well into the spring, an outcome Clinton desperately hopes to avoid.

She wants to pivot her high-tech organization into a general election machine capable of overcoming the apparent “enthusiasm gap” between Democrats and Republicans.

For example, the latest CNN/ORC International poll found 36 percent of Republicans and Republican-leaning independents said they were “very enthusiastic” about voting for president next year, compared to just 19 percent of Democrats and Democratic-leaning independents.

The more cash Sanders receives, the longer he can hang around and potentially distract Clinton. A protracted battle could become hostile and further taint liberals’ opinion of Clinton, perhaps causing them to stay at home on Election Day in November.