Bill Burton, shown during a news briefing at the White House in January, is now with pro-Obama superPAC Priorities USA Action. He says the superPAC is "careful to make sure that we are in compliance with the rules."
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Casino owner Sheldon Adelson and his wife, Miriam, at the Marina Bay Sands complex in Singapore in June. The Adelsons have donated $5 million each to the pro-Gingrich superPAC Winning Our Future.
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Dozens of televisions display a political advertisement with the image of GOP presidential hopeful Newt Gingrich at a store in Urbandale, Iowa, on Dec. 27. Republican candidates and their superPACs have spent millions on television and radio ads.
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