Heart of Darkness: Criminal Investigation of WI Recall $
"The controversy immediately kicked off a struggle for control of the Wisconsin Senate. Between 2011 and 2012 Wisconsin voters across the state knocked on doors, circulated recall petitions, and put an unprecedented number of state officials up for recall. Thirteen state senators eventually faced recall elections. Close to one million people signed recall petitions for the Governor and Lt. Governor, and even before an election was certified, outside money began to saturate the state. $137.5 million is estimated to have been spent on the recalls in total, the vast majority from out-of-state players.
The source of much of that spending remains unknown. Millions were spent by "dark money" nonprofits -- most of them organized under 501(c)(4) of the tax code -- that allow deep pocketed donors to hide their identity."
