Madison - Gov. Scott Walker raised an unprecedented $13.2 million over three months to fight off the recall bid against him, outdistancing his Democratic challengers and driving home the challenge they will have in beating the Republican incumbent.

Crisscrossing the country on fundraising trips, Walker has raised more than $25 million since January 2011 and has $4.9 million in cash on hand - numbers unlike any that have been seen for a political candidate in Wisconsin. Two-thirds of Walker's money came from out of state.

His stores of cash dwarf what his Democratic rivals have raised. But a report filed Monday showed an independent group supporting Democrat Kathleen Falk received $4.5 million, nearly all of it from unions and about a third of it from out of state.

Walker's fundraising is on par with that of second-tier presidential candidates. For instance, Rick Santorum raised $18.5 million between Jan. 1 and March 31, and Newt Gingrich raised a little less than $10 million during that period.

Walker has been able to raise so much because of the national appeal he developed with conservatives after his high-profile fight with labor unions and a quirk in Wisconsin law that allows unlimited fundraising while recalls are pending.

Conservative billionaire Diane Hendricks gave Walker $500,000. Hendricks co-founded Beloit-based ABC Supply, a roofing wholesaler and siding distributor, with her husband, Ken, who died in a 2007 fall.

Her donation was the single largest ever to a gubernatorial candidate in the state and tied the $500,000 given to Walker over recent months by Bob Perry, owner of Houston-based Perry Homes and a chief backer of the Swift Boat Veterans ads against Democrat John Kerry in the 2004 race for president.

"Wisconsin's never seen anything like this kind of money," said Jay Heck, executive director of Common Cause in Wisconsin. "This is all to persuade a relatively tiny universe of undecided voters. It'll be the highest cost per voter spent in the history of the nation in terms of the cost of persuading people."

A Journal Sentinel analysis showed that $4.4 million of Walker's money, or a third of the total, came from Wisconsin donors. The rest came from out of state.

Normally, donors can give a maximum of $10,000 to a candidate for governor. But from the time recall petitions are taken out to the time a recall election is called, donors can give any amount.

No fundraising limit was in place for Walker for about two-thirds of the period covered in the latest report. The Democrats had to follow the normal fundraising limits the whole time because they were not the targets of a recall.

In addition to the $500,000 donation from Hendricks, Walker received two $250,000 donations in the latest period. One came from Las Vegas Sands president Sheldon Adelson, a billionaire casino mogul who, along with his wife, put $17.5 million into Winning the Future, a super PAC supporting Gingrich.

Also giving $250,000 was Richard DeVos, the co-founder of the parent company of direct marketing firm Amway. DeVos has been active in the school voucher movement, and Walker last year expanded Milwaukee's voucher program and established a similar one in eastern Racine County.

Five people gave the governor $100,000 each - John Childs of Massachusetts, chairman of private equity firm J.W. Childs Associates; Warren Stephens of Arkansas, chairman of financial services company Stephens Inc.; Robert Kern, founder of Waukesha power-generating firm Generac; his wife, Patricia Kern; and Patrick Ryan of Illinois, CEO of insurance firm Ryan Specialty Group.

Challengers' tallies

The Democrats raised little compared with Walker. Falk, a former Dane County executive, raised $977,000 and had $118,000 on hand. Milwaukee Mayor Tom Barrett raised $831,500 and had $475,500 on hand.

Barrett didn't get into the governor's race until March 30 - 2½ months after Falk - but had nearly $500,000 to start, left over from his recent mayoral campaign.

Barrett is vying with Falk to win the May 8 Democratic primary and take on Walker in the general recall election June 5. Also running as Democrats are Secretary of State Doug La Follette and state Sen. Kathleen Vinehout of Alma.

La Follette's campaign is largely self-funded, with $112,000 of his $118,000 coming from his own pocket. Vinehout raised $44,000.

The fundraising reports for recall candidates were due with state elections officials Monday and run from Jan. 1 through April 23 for the Democrats and from Jan. 18 to April 23 for Walker.

Walker has been running a series of ads for months, as evidenced by the more than $11 million he has spent since mid-January. He had $4.9 million on hand as of April 23.

"We continue to see strong grass-roots support for Governor Walker, his bold reforms, and his plans for moving Wisconsin forward," said Walker spokeswoman Ciara Matthews. "Because of the overwhelming support for the governor, we can continue to speak to voters about how Governor Walker plans to move Wisconsin forward while his Democrat opponents plan to take Wisconsin backwards to higher taxes, record job loss and massive deficits."

Democrats countered that Walker was playing to a national audience instead of taking care of business in Wisconsin.

"While Wisconsin loses more jobs than any other state, Gov. Walker has spent his time trying to save his own job," Falk said in a statement. "He raised $13 million from across the country because he's delivered an extreme agenda that isn't our Wisconsin values, and I'm proud to stand with the nearly one million people who have signed a recall petition to remove him from office."

An expensive race

The flurry of fundraising shows how much more costly the recall election will be than previous elections for governor. In the 2010 race, candidates and independent groups spent an estimated $37.4 million, according to estimates by the Wisconsin Democracy Campaign.

That spending included $11.3 million by Walker and Lt. Gov. Rebecca Kleefisch. The losing Democrat ticket of Barrett and former Assembly Majority Leader Tom Nelson spent $7.2 million.

Outside groups such as the Republican Governors Association and the liberal Greater Wisconsin Committee spent an estimated $12.1 million to run television ads and send mailings to voters, and former U.S. Rep. and home builder Mark Neumann doled out $6.6 million - largely his own money - in a losing bid against Walker in the GOP primary for governor.

Such independent groups are operating in the recall election as well. The Republican Governors Association and Wisconsin Manufacturers & Commerce are running ads to help Walker.

On the left, the Greater Wisconsin Political Fund is running an anti-Walker spot, and Wisconsin for Falk is running ads and sending mailers to boost Falk.

Wisconsin for Falk received $4.5 million in donations, spent $3.9 million and had $517,000 on hand, according to a report filed Monday. It received $3 million from the Wisconsin Education Association Council, $1.3 million from the American Federation of State, County and Municipal Employees and $100,000 from the United Food and Commercial Workers union. The AFSCME and UFCW money came almost entirely from their Washington, D.C., offices.

Some other groups are able to mask their spending and fundraising.

Also facing recall is Kleefisch, who raised more than $540,000 from Jan. 18 to April 23. Her chief rival is Madison firefighter Mahlon Mitchell, but he had not filed his report as of 7 p.m. Reports were due by midnight.

Lori Compas, who is taking on Senate Republican Leader Scott Fitzgerald of Juneau, raised $104,600, spent $19,500 and had $84,200 in cash on hand. Fitzgerald had not filed as of deadline.

Sen. Van Wanggaard of Racine received $130,700, spent $52,400 and had $191,000 on hand. He received a $15,000 donation from Jere Fabick, president and CEO of Fabco Equipment Inc. in Milwaukee.

Other Senate recall candidates, including Wanggaard's opponent, former state Sen. John Lehman, had not filed as of deadline.

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$500,000 donors to Walker

Diane Hendricks, co-founder of Beloit-based ABC Supply, a roofing wholesaler and siding distributor.

co-founder of Beloit-based ABC Supply, a roofing wholesaler and siding distributor. Bob Perry, owner of Houston-based Perry Homes and a chief backer of Swift Boat Veterans ads against John Kerry in 2004 presidential race.

$100,000 donors to Walker

John Childs of Massachusetts, chairman of private equity firm J.W. Childs Associates

of Massachusetts, chairman of private equity firm J.W. Childs Associates Warren Stephens of Arkansas, chairman of financial services company Stephens Inc.

of Arkansas, chairman of financial services company Stephens Inc. Robert Kern, founder of Waukesha power-generating firm Generac

founder of Waukesha power-generating firm Generac Patricia Kern, wife of Robert Kern

wife of Robert Kern Patrick Ryan of Illinois, CEO of insurance firm Ryan Specialty Group

Ben Poston of the Journal Sentinel staff contributed to this report.