Cowles' seat is considered one of the safest among Republicans in the Senate. A fiscal conservative with significant environmental credentials, Cowles has been in the Senate for nearly 25 years. He ran unopposed in 2008 and won his 2004 reelection with nearly 90 percent of the vote.

Cowles said that despite the recall effort, he feels "comfortable in my skin" and stands by his record.

"I consider myself a budget hawk, before it was cool to do it," Cowles said. "I'm a balanced legislator, I've got the record to prove it and nobody is going to outwork me in the Legislature or in my district."

Cowles said he plans to review the signatures for possible challenges. GOP senators Dan Kapanke of La Crosse and Randy Hopper of Fond du Lac have already challenged signatures on other petitions on the ground that they were not properly filed. Lawyers for the recall committees have called the challenges "hypertechnical" and "devoid of merit."

The Democratic Party of Wisconsin claims signatures targeting three Democrats were fraudulently collected and plans to challenge those petitions as well.