WASHINGTON – Minnesotans poured more than $1 million into Democratic presidential hopeful Hillary Clinton's campaign in 2015, but new campaign finance records show that Vermont Sen. Bernie Sanders began gaining rapidly late last year.

On the Republican side, Minnesotans gave more than $1 million, sending the most to retired neurosurgeon Ben Carson, former Florida Gov. Jeb Bush and Texas Sen. Ted Cruz.

The contribution numbers come after the Iowa caucuses offered the nation's first test of the candidates and less than a month before Minnesotans caucus as part of Super Tuesday, a crucial series of caucuses and primaries in 15 states.

"Money is clearly calibrated by enthusiasm and support," Hamline University political scientist David Schultz said.

Minnesotans gave more than $2.5 million to the presidential race in 2015, a year when the state lacked a U.S. Senate or gubernatorial contest. Of that, $1.14 million went to Republican presidential candidates and the rest went to Democrats.

Among Republicans, Carson received the most at $326,387, Bush received $216,342 and Cruz received $199,106 from Minnesotans.

Real estate mogul Donald Trump, who tops national polls and came in second in Iowa earlier this week, took in $8,762 from Minnesotans.

Cruz and Sanders are catching a surge of momentum nationally after Iowa, where Cruz secured a commanding victory over GOP rivals and Sanders lost to Clinton by a razor-thin margin.

The numbers from October through December show that Sanders and Cruz were generating a wave of excitement among Minnesota donors. Clinton still took in more money than Sanders in the fourth quarter, but he was quickly catching up, raising $159,000 to her $219,000 in the last three months of 2015.

Carson brought in $138,131 and Cruz hauled in $131,223 during the fourth quarter — the highest among all of the Republicans.

A Star Tribune analysis of contributions between $201 and $499 in 2015 showed Clinton and Sanders with a similar number of people contributing in those smaller amounts. That means Clinton's hefty lead is coming from a larger number of donors making the maximum allowable donations to her campaign.

This also means that Sanders has more contributors who haven't reached federal limits, the kind of donors he can return to for more money. These numbers don't include contributions below $200, which aren't required to be itemized by campaigns to the federal election officials.

"I think it speaks to enthusiasm in different ways and it speaks to the potential for Sanders to go back to his existing base and raise more money," said Hamline's Schultz.

The Sanders campaign points to what it sees as a groundswell of support, in terms of both volunteers and money. Nationally, 1.5 million people made $3.5 million in contributions. In Minnesota, there were 100 volunteers who took road trips to Iowa to bolster grass-roots support there.

With the Iowa caucuses over, campaigns have shifted attention back to Minnesota for the next few weeks.

"We're very singular in our mission, which is to take our message directly to the voters of Minnesota," said Robert Dempsey, Sanders' state director.

Larger campaign contributions can be indicative of an older supporter base — something Clinton is clearly working on in Minnesota. Her campaign dispatched her daughter, Chelsea Clinton, to the Twin Cities on Wednesday to host three events targeting women and working families.

"We've activated over a thousand volunteers who all believe Hillary is the one candidate in this race who can create real change for Minnesota families," said Scott Hogan, Clinton's head Minnesota organizer, in a statement.

Among Republicans, Carson and Cruz lead among the number of contributors who gave between $201 and $499.

Schultz said this comes straight out of the playbook of another former GOP presidential hopeful: former U.S. Rep. Michele Bachmann.

"Bachmann was getting $25 contributions, and then she'd go back to the same donors for another $10," he said.

Cruz's Minnesota director, Brandon Lerch, said his candidate's Iowa win validated all of the work his campaign did to reach out to voters all across the state. He noted that Cruz has received contributions from each of Minnesota's 87 counties.

"We're finally going to see the results of two different minds in how to run a Republican campaign," said Lerch, comparing Cruz to Trump, who relied mostly on media and marketing to get voters turned out. "I can tell you we're making calls in every single corner of Minnesota. That's the kind of campaign Cruz runs."

Florida Sen. Marco Rubio, who came in a close third in Iowa this week, has many influential Republicans on his side in Minnesota. His state leadership team is a long list of high-profile state GOP supporters — including Jeff Johnson, the Hennepin County commissioner and former gubernatorial candidate.

But his fundraising lags way behind the others. Rubio pulled in $77,304 from Minnesotans in 2015 — almost the same as Wisconsin Gov. Scott Walker and Kentucky Sen. Rand Paul. In the fourth quarter, he pulled in only $39,380.

Rubio's campaign says his momentum is just starting.

"Coming off an impressive showing in Iowa last night and our strongest fundraising quarter of the campaign, we are optimistic," said Jeremy Adler, a campaign spokesman. "We already have a strong team on the ground in Minnesota and are confident that they will work to make sure Marco's optimistic message … resonates."

Allison Sherry • 202-383-6120