Organizers of an effort to recall Wisconsin Gov. Scott Walker turned in more than 1 million signatures, almost double what they needed, to force an election.

Update at 4:55 p.m. ET: United Wisconsin, which organized recall petition campaigns against Walker and other elected Republicans, turned in a total of 1.9 million signatures to the Government Accountability Board, the Wisconsin State Journal says. Of those, more than a million signatures were on petitions to oust Walker and 845,000 to recall Lt. Gov. Rebecca Kleefisch. More than 21,000 signatures apiece were gathered against Republican Sens. Pam Galloway of Wausau, Van Wanggaard of Racine and Terry Moulton of Chippewa Falls.

Earlier today, leaders of the effort to recall Senate Majority Leader Scott Fitzgerald filed 20,600 signatures.

Original post: Organizers of an effort to recall Wisconsin Gov. Scott Walker say they have collected more than 1 million signatures -- twice what they need -- to force an historic recall election, the Wisconsin State Journal reports.

Democrats need to submit 540,208 valid signatures to schedule a recall election against Walker, a Republican who was elected in 2010.

The Milwaukee Journal Sentinel also reports that the recall organizers will officially file petitions with more than 1 million signature this afternoon.

If a recall election is mounted, it would be the first in state history. There have been only two successful recalls of a governor in U.S. history, in North Dakota in 1921 and California in 2003.

Former U.S. representative David Obey, who has been in state politics for a half century, called the recall effort "an amazing development," the Journal Sentinel reports.

The Journal notes that the number of signatures, if accurate, would nearly match the 1.12 million votes Walker got in the gubernatorial election.

The delivery of petitions is only the first step in a long process. First comes the validation process, which could take months.

Then Democrats would have to select a candidate to run against Walker. That potentially could involve a primary election first before a face-off with the governor.

Walker angered Democrats and unions by pushing through legislation to curb the power of public unions.

The legislative effort led Democratic lawmakers at one point to leave the state to deny a quorum needed to pass the measure.