Signatures have been filed for the recalls of four Republican state senators, and organizers on both sides of the political divide say that more are to come.

The state Government Accountability Board (GAB) has received signatures requesting recalls of Republicans Sheila Harsdorf of River Falls, Randy Hopper of Fond du Lac, Dan Kapanke of La Crosse and Luther Olsen of Ripon.

No petitions have yet been filed against a Democrat, although organizers say that they will have enough signatures to request recalls against state Sens. Jim Holperin of Conover, Dave Hansen of Green Bay and Bob Wirch of Pleasant Prairie.

The GAB and the campaign committees will be able to challenge and verify the submitted signatures. If enough signatures pass the challenges, a recall election will be held for the individual senators.

State Rep. Jen Shilling (D-La Crosse) has announced she'll challenge Kapanke, while Oshkosh Deputy Mayor Jessica King will run against Hopper if a recall election is called.

Both Kapanke and Hopper are considered to be weak due to their support for Gov. Scott Walker's agenda and their questionable personal ethics.

Kapanke unsuccessfully ran for Congress in 2010, and was forced to admit to unintentionally violating state ethics rules when he paid off personal debt with charity money.

Hopper beat King by 163 votes in 2008. But that was before Hopper became a vocal supporter of Walker and became embroiled in a contentious divorce. Hopper's alleged girlfriend left her position in a lobbying firm to work in the Walker administration—and received a 35% raise over her predecessor. Hopper's estranged wife is supporting the recall efforts and claims he lives in Madison with his girlfriend, not in the district.

Olsen is also vulnerable, since the top employers in his district are prisons and schools. Olsen voted to significantly reduce the collective bargaining rights of both corrections employees and teachers.

Harsdorf represents a swing district and seems to have angered those who oppose her support of Walker's agenda.

Target: Alberta Darling

Locally, the biggest target is state Sen. Alberta Darling (R-River Hills), the co-chair of the Joint Finance Committee, which is holding contentious public hearings on Gov. Scott Walker's unpopular budget bill. Darling has supported Walker's agenda and voted for his controversial collective bargaining bill in March. Her opponents are highlighting her tight connection to the divisive governor.

Mike Tate, chair of the Democratic Party of Wisconsin, said he's confident that organizers will have enough signatures to force a Darling recall. Although the district is ideologically mixed and re-elected Darling in 2008 in a Democratic year, Tate said that gathering 20,343 signatures by May 2 to force a recall election wouldn't be a problem.

"I have no doubt that we are going to get the amount of signatures that we need," Tate said. "But we are doing a very thorough vetting of the signatures that we're getting from the activists on the ground. There is so much enthusiasm that we are seeing people signing who don't live in the district."

He said forcing Darling out of office via a recall "is doable but a challenge."

Tate said those who support recalling Darling and other Republicans should visit recalltherepublican8.com and donate either to the state Democratic Party or to the recall committees.

Andrew Davis, Darling's campaign manager, said that his team is taking the recall effort "very, very seriously. We are doing everything we can to stop it."

He said Darling has hired campaign staff and has opened a second campaign headquarters, in Germantown, in addition to her main campaign office on Silver Spring Drive. Volunteers have been trying to promote Darling within the district.

"We're very confident that we're getting our message out," Davis said.

Brad Courtney, chair of the Republican Party of Wisconsin, did not respond to the Shepherd's request to comment on the recall efforts.