By Brendan O'Brien
MILWAUKEE (Reuters) - Wisconsin Republican Governor Scott Walker said on Monday his campaign raised $13 million in just over three months to ward off an attempt by Democrats and unions to remove him from office in a recall election because of his attacks on organized labor.
The first-term governor, who faces the expensive special election in June, raised that amount between January 17 and April 23, according to a finance report filed with the state.
The $13 million represents more than seven times the combined amount raised by his two main Democratic challengers - Milwaukee Mayor Tom Barrett and former Dane County Executive Kathleen Falk, according to finance reports.
Barrett reported that he raised $831,508 since he joined the race to unseat Walker on March 30. Falk said she raised $977,059 since she joined the race on January 17.
Walker is a celebrity among conservatives, who have opened their checkbooks for him because he has taken on public sector unions in Wisconsin. Walker has made at least three trips out of state to raise money since the end of March.
But Walker is also spending money at a brisk pace and he had $4.8 million in cash on hand on April 23, according to the official filing. Walker has raised more than $25 million since he took office in January 2011.
Walker enraged Democrats and unions representing government workers such as teachers when he pushed through the legislature last spring a measure drastically reducing their powers. The law forced them to pay a portion of the cost of health insurance and pensions, capped wage increases, and required unions to be recertified every year.
Opponents gathered nearly a million signatures to recall Walker and a vote will be held on June 5 to decide between Walker and a Democrat chosen in a May 8 primary.
"We continue to see strong grassroots support for Governor Walker, his bold reforms, and his plans for moving Wisconsin forward," Walker spokeswoman Ciara Matthews said after the financial report was submitted.
His opponents said he was trying to buy the election.
"Instead of spending his energy and attention raising money at $250,000 per check from out-of-state, right-wing ideologues, Scott Walker should have paid more attention to his failed promise to create 250,000 jobs here in Wisconsin," Barrett spokesperson Phillip Walzak said.
Democrats are pounding Walker over a recent report that said Wisconsin had lost more jobs than any state in the nation over the past year.
Among Walker's supporters are Charles and David Koch, billionaire brothers who have used their wealth from trading and commodities company Koch Industries to support conservative causes.
Polls show the recall election could be close, with Wisconsin voters evenly split and only a small number of undecided voters. If Walker loses, he would be only the third U.S. governor removed from office during his term.
On Tuesday, New Jersey Governor Chris Christie, who also has confronted unions, is expected to arrive in Wisconsin for two fundraisers for Walker.
An independent campaign finance expert in Wisconsin has said that spending by both sides in the recall election could reach a record $60 million.
(Writing by Greg McCune; Editing by Dan Burns and Will Dunham)