The United Wisconsin coalition said Thursday that more than 507,000 signatures were collected in just 30 days. They need about 33,000 more to trigger a recall election sometime in 2012. Petitions are due Jan. 17.
The coalition says its goal is to collect 720,000 signatures.
The effort was spurred by anger over Walker's proposal effectively ending collective bargaining rights for public workers.
The state elections board is planning to take 60 days to review the submitted petitions. The burden of challenging the validity of signatures, and tossing out duplicates, rests with Walker.
Copyright 2011 The Associated Press.