Former New York City Mayor Michael Bloomberg speaks on behalf of Bloomberg Philanthropies Aug. 5 during the U.S.-Africa Business Forum. Bloomberg had been expected to commit most of his post-mayoral time to his charitable work, but said he found the day-to-day dealings at his media company to be too intriguing to stay away. Saul Loeb/AFP/Getty Images hide caption

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New York Mayor Michael Bloomberg speaks during a press conference in London in September. Matt Dunham/AP hide caption

itoggle caption Matt Dunham/AP

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

itoggle caption Jae C. Hong/AP