by Kim Barker, ProPublica
Karl Rove's Crossroads GPS and Americans for Prosperity, a group backed by the Koch brothers, have put almost $60 million so far into ads to influence the presidential race, an analysis of new spending estimates shows.
These nonprofits, also known as 501(c)(4)s or c4s for their section of the tax code, don't have to disclose their donors to the public.
The two nonprofits had outspent each of the other types of outside spending groups in this election cycle, including political parties, unions, trade associations and political action committees, a ProPublica analysis of data provided by Kantar Media's Campaign Media Analysis Group, or CMAG, found.
Super PACs, which do have to report their donors, spent an estimated $55.7 million on TV ads mentioning a presidential candidate, CMAG data shows. Parties spent $22.5 million.
Crossroads GPS, or Crossroads Grassroots Policy Strategies, is the brainchild of GOP strategist Karl Rove, and spent an estimated $41.7 million. Americans for Prosperity, credited with helping launch the Tea Party movement, is backed in part by billionaire brothers David and Charles Koch, and spent an estimated $18.2 million.