Washington – In the most competitive congressional races in Minnesota and nationwide, the Democratic candidates combined are raising more money than their Republican rivals.

Campaign finance reports for the top House candidates in the 52 most-competitive districts, as identified by the Rothenberg Political Report, show Democrats with $41.8 million in the bank, compared with $30.1 million for Republican candidates.

The strong first-quarter hauls for Minnesota incumbent Democrats Rick Nolan and ­Collin Peterson typify the broader financial landscape.

Facing stiff election challenges, both ramped up their fundraising during the first three months of the year, expanding their leads in the chase for campaign cash.

Their seats are among the 52 nationwide that the nonpartisan Rothenberg Report considers up for grabs.

Through the end of March, Nolan had $478,000 banked for his re-election run in the Eighth District. That's 30 percent more than the $356,000 his Republican challenger, Stewart Mills III, had in his campaign ­coffers.

Peterson has $522,000 in the bank, three times more than the $171,000 his GOP opponent, state Sen. Torrey Westrom, has in cash reserves.

The National Republican Congressional Committee (NRCC) has tapped Mills and Westrom for their "Young Guns" program, which lends support to the party's most promising candidates in ­competitive districts.

Yet, in the most competitive races, Democratic incumbents targeted by the NRCC have, on average, twice as much money stocked away as their GOP challengers.

Mills, whose family founded Mills Fleet Farm, noted that political action committees had supplied more than half of Nolan's total campaign contributions. In response, the Nolan campaign said it notched a tenfold increase in small-donor donations during the first three months of the year.

Peterson, the ranking Democrat on the House Agriculture Committee, has relied on PAC contributions as well. Close to 80 percent of his campaign contributions for this election cycle have come from political action committees, most of them with ties to agriculture. Westrom, who is running his first congressional campaign, did not respond to a request for comment.

Drawing the most campaign contributions won't help Peterson and Nolan to outrun their voting records, said NRCC spokesman Tyler Houlton.

Cash matters – a lot

Fundraising figures are one — though by no means the only — measure of enthusiasm for a candidate's campaign.

Lackluster fundraising by Democratic candidates in Minnesota's Second District led the Rothenberg Report to downgrade Democrats' chances at snatching the seat from Republican Rep. John Kline.

Kline has an 8-to-1 cash advantage over the leading Democratic fundraiser in the district, former state Rep. Mike Obermueller. The seat is now considered "Safe Republican."

Incumbents typically raise more money than their challengers, and Minnesota's ­congressional races are no different.

Nolan and Peterson feared that poor fundraising at the start of 2014 would provide Republicans with another ­rallying point.

Until Nolan's surge during the first three months of the year, Mills had outraised Nolan in two consecutive ­fundraising periods.

With little time to raise cash after announcing his re-election plans in mid-March, Nolan made up ground by hosting four fundraisers during the final week of March.

There's more money to come

The incumbents may need the cash-on-hand advantage as independent groups jump in and spend heavily on broadcast ads to influence the outcome of tightly contested races.

Big spenders on the right and left are planning to pour millions of dollars into television advertisements for and against the candidates in the key congressional races.

GOP groups, including the NRCC, already have spent close to $250,000 on ads targeting Peterson in his western Minnesota district. Outside groups on both sides spent more than $10 million in Nolan's 2012 House race, in which he defeated first-term incumbent Chip Cravaack, and the spending in 2014 is already underway.

The American Action Network, a nonprofit founded by former Minnesota Sen. Norm Coleman, and Americans for Prosperity, the conservative advocacy group backed by the Koch brothers, already have aired TV ads attacking Nolan's record.

Nolan has deep-pocketed donors on his side as well.

House Majority PAC, the leading super PAC backing Demo­cratic U.S. House candidates, has reserved nearly $330,000 for fall television advertisements in Nolan's ­district.

Corey Mitchell is a correspondent in the Star Tribune Washington Bureau. Twitter: @C_C_Mitchell