While wealthy liberal donors and left-leaning groups have caught up with conservatives in some areas of independent political spending, Republicans continue to dominate among politically active nonprofits that are not required to disclose their donors, according to the Sunlight Foundation. The nonpartisan watchdog group's analysis of Federal Election Commission filings found that pro-Republican 501(c)(4) and 501(c)(6) organizations have reported spending $94.6-million on midterm races, more than triple the tally for groups that lean Democratic.
The U.S. Chamber of Commerce accounts for about a quarter of the "dark money" activity, spending $31-million, almost of all it to support GOP candidates or attack Democrats. Republican operative Karl Rove's Crossroads GPS has spent some $23-million. The most active pro-Democrat organizations, the League of Conservation Voters and Patriot Majority USA, have spent about $9.5-million and $8.5 million, respectively. Much of the money from both sides is flowing into a handful of states with tight Senate races.