Casino magnate Sheldon Adelson at the presidential debate between Mitt Romney and President Obama, in Denver on Oct. 3. Adelson invested millions in an effort to help elect Romney — but only after bankrolling a superPAC for former House Speaker Newt Gingrich in his anti-Romney Republican primary battle. Nicholas Kamm/AFP/Getty Images hide caption

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Karl Rove, former adviser to President George W. Bush, speaks last year in Corpus Christi, Texas. Rove is the chief fundraiser for the biggest outside spender this election season: the twin groups American Crossroads and Crossroads GPS. Michael Zamora/AP hide caption

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Former Virginia Gov. Tim Kaine is joined by his wife and daughter in celebrating his Senate victory over Republican George Allen. Mike Theiler/UPI /Landov hide caption

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Karl Rove, the founder of Crossroads GPS and a former adviser to President George W. Bush, at the Republican National Convention in Tampa, Fla., on Aug. 28. Spencer Platt/Getty Images hide caption

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U.S. Sen. Sherrod Brown (right), D-Ohio, debates his Republican challenger, Ohio state Treasurer Josh Mandel, at the City Club in Cleveland on Oct. 15. Tony Dejak/AP hide caption

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Sheldon and Miriam Adelson attend the opening ceremony of Four Seasons Hotel in Cotai Strip in Macau, Aug. 28, 2008. Kin Cheung/AP hide caption

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Former Maine Gov. Angus King, an independent candidate for the U.S. Senate, greets potential voters Oct. 1 in Bath, Maine. Joel Page/AP hide caption

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Costumed demonstrators on Oct. 3 in Denver, before the first presidential debate. Doug Pensinger/Getty Images hide caption

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