Jane Corwin, the Republican candidate in New York's 26th congressional district, votes in Clarence, N.Y., on Tuesday. David Duprey/AP hide caption

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President Obama pats AFL-CIO President Richard Trumka on the back before speaking at the AFL-CIO Executive Council Meeting in Washington last August. Trumka said recently that unions need to start demanding accountability from their allies. Jim Watson/AFP/Getty Images hide caption

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President Obama participates in an AARP tele-town hall on health care in July 2009. The seniors group lobbied hard for the president's health care law. Now, Republicans say the group stands to make a healthy profit from the law. Haraz N. Ghanbari/AP hide caption

itoggle caption Haraz N. Ghanbari/AP

Last fall, Oregon Rep. Peter DeFazio was the subject of a political ad paid for by the Concerned Taxpayers of America — which turned out to be a million-dollar front group financed by just two men. Read more about that ad, and how DeFazio followed the money. Jonathan Ernst/Getty Images hide caption

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Former House Speaker Newt Gingrich, speaking at a news conference Thursday in Atlanta, says he is launching a website to explore a run for president. Mike Stewart/AP hide caption

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Demonstrators gathered outside the Ohio Statehouse last week to protest Senate Bill 5, which would have banned collective bargaining for state workers. Unions say legislation being pushed by Republican governors nationwide is an attack on their very existence. Jay LaPrete/AP hide caption

itoggle caption Jay LaPrete/AP