By Brendan O'Brien
MILWAUKEE (Reuters) - Wisconsin is set on Friday to launch a special election that could oust Republican Governor Scott Walker from office because of his support for a law stripping labor unions of power, the first recall election of a U.S. governor since California nearly a decade ago.
Almost a million of Wisconsin's 4.4 million voting-age population signed a petition to recall the controversial governor, nearly twice the number needed to force an election.
Staff of the Wisconsin agency which manages elections said on Thursday that there were enough valid signatures to trigger the election, which is expected in May or June. The agency, the Government Accountability Board, will meet on Friday to formally certify the signatures and set the date.
Not since California Democrat Gray Davis was booted from office in 2003 has the governor of a state faced such a revolt. In the case of California, voters cast ballots on whether to retain or oust Davis. Separately, the cast ballots on a new governor and actor Arnold Schwarzenegger was elected.
Wisconsin's law is unusual because the vote will not be on whether to boot Walker, but between Walker and a Democratic opponent. Democrats must choose an opponent for Walker in a primary.
The race could well be a rematch of the 2010 election, when Walker narrowly defeated Milwaukee Mayor Tom Barrett. Barrett has not yet said if he will run.
Shortly after taking office in 2011, Walker set off a firestorm when he championed a law to strip public sector unions of most of their powers.
The law, passed last spring by the Republican-led legislature, forced public sector workers to pay part of the cost of health insurance and pension, and took away union power to negotiate wage increases beyond the level of inflation. But what most infuriated unions was a provision that required them to be recertified by a vote of membership every year, which threatened their existence.
The law sparked weeks of pro-union protests at the capital in Madison and Senate Democrats fled the state in a futile attempt to stop the measure from becoming law.
Walker said the measure was needed to close a budget gap and put Wisconsin on a firmer financial footing.
Despite the outrage from unions and Democrats, a poll this week suggested Wisconsin is closely divided, with Walker holding a slight edge over Barrett.
Barrett, who is standing for reelection as Milwaukee mayor against token opposition on April 3, has said he would announce whether he is running for governor before Tuesday.
Barrett held a fundraiser on Wednesday in Milwaukee, attended by Chicago Mayor Rahm Emanuel, fueling speculation that he is leaning toward a gubernatorial bid.
According to the poll of 707 registered and eligible voters released by Marquette Law School earlier this week, Barrett would win a primary against current Democrat candidates with 36 percent of the vote.
Among the other Democrats, former Dane County Executive Kathleen Falk would receive 29 percent of the vote, and state Senator Kathleen Vinehout and Secretary of State Doug La Follette would receive 8 percent each. Another 17 percent of respondents were undecided.
Walker still had a slight edge over Barrett in a general election at 49 percent to 47 percent. Walker led Falk 49 percent to 45 percent. The Democratic primary poll had a 5.2 percent margin of error and the general election poll 3.8 percent.
In addition to Walker, four Republican state Senators who voted for the union curbs, and Walker's Lieutenant Governor Rebecca Kleefisch, would also face recall elections.
Wisconsin in the last year has held more recall elections than any of state in modern U.S. history. Nine state Senators faced recall last summer and two were ousted.
Once the recalls are completed this year, some 40 percent of the Wisconsin state Senate will have faced a special election in the last year.
(Reporting by Brendan O'Brien; Editing by David Bailey and Greg McCune)