Russ Feingold has represented Wisconsin in Congress over the last three decades, and has been the Badger State's senator since 1993. Known as a highly principled politician, Feingold has broken with his fellow Democrats by voting against legislation like financial reform and being the lone vote against the USA PATRIOT Act. But perhaps he's best known for a campaign finance reform law that bares his name, McCain-Feingold. That law, which banned "soft money," or unregulated contributions, from elections was struck down earlier this year by the Supreme Court in the Citizens United case.

But this fall, this longtime incumbent faces the toughest re-election bid of his career. Feingold has been overtaken in the polls by the self-funded political newcomer and millionaire, Ron Johnson.

Yesterday, the Supreme Court effectively overturned The Bipartisan Campaign Reform Act, the campaign finance reform passed in 2002.  Senators John Mcain (R-Ariz.) and Russ Feingold (D-Wisc.) designed the law to limit the influence of big business and labor unions on elections.