A demonstrator holds a "Stop Trump 2016" sign across the street from an April 25 Donald Trump rally, in West Chester, Pa. Bloomberg/Bloomberg via Getty Images hide caption

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Progressive SuperPACs Ramp Up Their Big-Money Effort Against Donald Trump
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Supporters cheer in Colorado Springs, Colo., as a television broadcast declares that Republicans have taken control of the Senate. Republican candidates, party committees and outside groups spent about $44 million more than Democrats, according to the Center for Responsive Politics. Marc Piscotty/Getty Images hide caption

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Among outside groups — that is, not candidates or party committees — more than half of this cycle's political ads are financed by secret donors. iStockphoto hide caption

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This Political Ad Was Paid For By — Oh, Never Mind
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The Ricketts family poses on the Chicago Cubs field in 2010, a year after they bought the team: Laura Ricketts (from left), Joe Ricketts, Marlene Ricketts, Todd Ricketts, Tom Ricketts and Pete Ricketts. Nam Y. Huh/AP hide caption

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A Political Family, Funding And Running On Both Sides Of The Aisle
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George Soros, seen at a forum in Berlin last year, joined a superPAC backing a Hillary Clinton presidential run in 2016. Sean Gallup/Getty Images hide caption

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U.S. Rep. Joe Baca of California, shown at the 2008 Democratic National Convention, learned the power of superPACs firsthand this year, when he lost for the first time since he was elected in 1999. Jae C. Hong/AP hide caption

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How To Oust A Congressman, SuperPAC-Style
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A supporter of President Barack Obama raises his arms as it is announced that Obama was re-elected during an election night watch party in Chicago. Jerome Delay/AP hide caption

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With Millions Spent, GOP 'Investors' Saw Little Return Election Night
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Voters participate in early voting Friday in Silver Spring, Md. Alex Wong/Getty Images hide caption

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Any Way You Describe It, 2012 Campaign Spending Is Historic
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The Campaign to Defeat Barack Obama, a small-donor PAC, has launched a bus tour to reach conservative voters in hotly contested states, while trying to raise money to launch an anti-Obama TV ad. Yfat Yossifor/Courtesy of Mlive.com hide caption

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With Buses And Billboards, Small-Money Groups Try To Make A Mark
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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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In Key Senate Races, Outside Groups Outpace Candidates' Ad Spending
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Las Vegas casino magnate Sheldon Adelson watches a performance at the Sands Cotai Central in Macau in April. Kin Cheung/AP hide caption

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Casino Owner Expected To Make $10M Donation To Pro-Romney SuperPAC
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