A super PAC that has opposed House incumbents from both parties in primary elections.
An environmental group launched in 1969 that targets a “Dirty Dozen” list of politicians for defeat.
A labor union that represents more than 1.6 million public sector employees and retirees.
A super PAC formed in 2013 with the goal of pushing the Republican Party further right.
A left-leaning super PAC founded and financed by former New York City Mayor Michael Bloomberg.
Affiliated Republican advocacy groups formed with the help of Ed Gillespie, former chairman of the Republican National Committee, and Karl Rove, an adviser to President George W. Bush.
Conservative PACs aiming to elect “true” conservatives to Congress and defeat incumbent Republicans that fall short of that standard.
A super PAC focused on maintaining and expanding the Republican majority in the House of Representatives.
A nonprofit trade group that advocates a pro-business agenda.
A major force behind the tea party movement, this conservative/libertarian group was founded by billionaire businessman David Koch.