MADISON, Wis. -

Wisconsin Democrats said they have gathered enough signatures to recall a Republican senator because of his vote on Gov. Scott Walker?s bill that cuts most collective bargaining rights for state employees.

Organizers on Thursday turned in more than the 15,629 signatures needed to start the recall for Fond du Lac Sen. Randy Hopper.

They presented the Government Accountability Board with 22,500 signatures to trigger a recall election.

"Our volunteers are extremely proud of the effort, the amount of hours that they put in, and the time we took off of work and also their families. They took time away from their families to come and help," said Scott Dillman, one of the recall organizers.

University of Wisconsin-Madison political science professor Barry Burden said Tuesday's elections gave a boost to the recall efforts, but forecasting a recall's ultimate success is tough to gauge.

"Although turnout was high, it was still 33 percent statewide. That's two thirds of the voters who are sitting aside, and we just don't know exactly who would participate in a recall," Burden said.

Burden said Hopper now joins a short list of senators with a realistic chance of losing a recall election. Democrats have already filed papers to recall Sen. Dan Kapanke of La Crosse.

Six other Republicans and eight Democrats are facing recalls for their support or opposition to the budget repair bill.

"There are 16 (senators) who are eligible to be recalled. I would guess we don't get signatures for all of those. Probably more of the efforts against the Republicans will be successful than Democrats, maybe 10 or a dozen of those will actually get enough signatures. But then you need opponents to run against them," Burden said.

In a statement, Hopper said he's confident that voters in the 18th Senate District will support his goal of making Wisconsin a place in which businesses and middle-class families can grow and prosper.

Burden said he also believes two Democrats could be close to losing their seats -- Sen. Jim Holperin from Conover and Sen. Julie Lassa of Stevens Point. Burden said recall momentum for both sides seems to be moving forward.

The law that would take away most collective bargaining rights from state employees is still in court in a legal battle.