The long awaited, much anticipated special election to decide the political future of Wisconsin Gov. Scott Walker became official Friday when the state Government Accountability Board certified recall petition signatures and set a date for the historic vote.

More than 900,000 valid signatures were collected on petitions circulated statewide, nearly twice the number needed for the board to order the state's first gubernatorial recall -- and only the third in the nation.

A primary election involving at least four Democratic challengers is set for May 8. A general election between Walker and the Democratic winner will take place June 5.

"We're ready," said Jesse Garza, chairman of the Hudson-based St. Croix County Republican Party. "The volunteers are ready. The campaigns are ready. It's going to be a short, fast, hard-running campaign. We have only about 60 days for voters to decide who it is they trust."

Said Lynn Freeman, executive director of United Wisconsin, a grass-roots group formed to recall Walker, "It's a little bit like being at the top of the roller coaster hill before you go down the other side."

While Friday's order was long expected, it sparked yet another round of passionate debate on a bitter issue that has divided the state and much of the nation since early 2011, when Walker moved to curb state spending by eliminating collective bargaining rights for most of the state's public employees.

Walker's opponents won a partial victory in court Friday, when a federal judge struck down part of the law that took away union rights. The court ruled that the state can't prevent public sector unions from automatically deducting dues from workers' paychecks and also cannot force them to face recertification every year. The court, however, upheld the elimination of their collective bargaining rights.

Walker supporters say they remain confident that a majority of voters back the governor.

"On June 5th, voters will be faced with a choice," said Ciara Matthews, communications director for Walker's campaign. "We believe the majority of voters, just as they did in 2010, will stand with Scott Walker."

Graeme Zielinski, a spokesman for the Democratic Party of Wisconsin, said he is confident momentum favors the Democrats. That more than 1 million signatures were initially delivered to the Government Accountability Board in January, he said, "is a testament to the overreach of Gov. Scott Walker."

"This is not cause for celebration," he added. "We'd rather not have this done. But this was brought on us by Gov. Scott Walker."

Few fakes and phonies

The Government Accountability Board determined that 900,939 recall petition signatures were valid; 540,208 were needed to order the election. About 30,000 signatures were eliminated because they were illegible, duplicates or contained inaccurate or incomplete information.

Among the phony signatures stricken: Adolf Hitler, Mick E. Mous, Donald L. Duck and I Love Scott Walker Thanks.

The board considered striking the name Fungky Van Den Elzen, believing it was a fake. A board attorney later determined it was legitimate.

Besides Walker, four state senators and the lieutenant governor are targeted for recalls.

But it's the outcome of the gubernatorial race, which many have framed as a fight to determine the fate of America's middle class, that has generated the most attention. Its outcome could spill over to November, when President Obama runs for re-election and voters decide who will control the U.S. Senate.

Mike McCabe, director of the Wisconsin Democracy Campaign, a watchdog group in Madison that tracks money spent on state elections, said advertising purchases and campaign finance reports show that special-interest groups, many from outside Wisconsin, are investing substantial sums in the race.

To date, Walker has raised more than $12 million, and has spent about $7 million "on television ads alone," McCabe said. "Once the Democratic nominee emerges, I think we'll see the spending pick up on the Democratic side. But so far, it's been pretty lopsided in favor of Walker."

McCabe said about $1.6 million has been spent by Wisconsin for Falk, a group funded largely by public unions in support of Kathleen Falk, a former Dane County executive.

Other Democrats who have announced their candidacies are state Sen. Kathleen Vinehout, of Alma, Secretary of State Doug La Follette and Milwaukee Mayor Tom Barrett, who lost to Walker in November 2010.

Garza, who was in Milwaukee on Friday in advance of a weekend event involving GOP presidential candidates, said the uptick in advertising in southeastern Wisconsin is noticeable, from highway billboards to TV ads.

"They are fighting for their own survival for unions down here," Garza said, "and they are going to put everything into this fight. But we are, too."

Said Freeman of the United Wisconsin group, "Now it's a matter of getting voters to turn out."

The Associated Press contributed to this report. Richard Meryhew • 612-673-4425