J. Russell George, Treasury inspector general for tax administration (from left), Acting IRS Commissioner Steven Miller and former IRS Commissioner Douglas Shulman before they testified to the Senate Finance Committee in 2013. Win McNamee/Getty Images hide caption

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All five of these people are running for president, but it looks like only one will make it into the first Republican debate. Darren McCollester/Getty Images hide caption

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Robert Gray of Jackson, Miss., who won the Democratic primary for governor, outside the governor's office at the state Capitol on Wednesday. Gray, a long distance truck driver, was a surprise winner, having spent virtually no money on advertisements and doing a limited amount of campaigning. Rogelio V. Solis/AP hide caption

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Republican presidential candidates, from left, Lindsey Graham, Ben Carson, John Kasich, Chris Christie, Bobby Jindal, Jeb Bush, Scott Walker and Rick Santorum speak among themselves after a forum Monday, Aug. 3, 2015, in Manchester, N.H. Jim Cole/AP hide caption

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"I don't like a government shutdown, but this is a clear case of totally improper use of taxpayers' dollars. I have an obligation to the taxpayers of Arizona," said Sen. John McCain. He had scolded his Republican colleagues in 2013 for shutting down the government over the Affordable Care Act. He says this issue is different. Mandel Ngan/AFP/Getty Images hide caption

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A coal scraper machine works on a pile of coal at American Electric Power's Mountaineer coal power plant in 2009 in New Haven, W.Va. The state, in which coal mining is a major industry, is one party planning to sue the Environmental Protection Agency regarding new power plant regulations announced Monday. Saul Loeb/AFP/Getty Images hide caption

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Texas billionaire H. Ross Perot laughs after saying, "Watch my lips," in response to reporters asking when he plans to formally enter the presidential race. Questions came May 5, 1992, in New York City, where Perot was speaking before the American Newspaper Publishers Association. Richard Drew/AP hide caption

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Former Florida Gov. Jeb Bush, Dr. Ben Carson, New Jersey Gov. Chris Christie, former CEO Hewlett-Packard Carly Fiorina, U.S. Senator Lindsey Graham, Louisiana Gov. Bobby Jindal, Ohio Gov. John Kasich, former New York Gov. George Pataki, former Texas Gov. Rick Perry, former U.S. Senator Rick Santorum (PA), Wisconsin Gov. Scott Walker stand on the stage prior to the Voters First Presidential Forum. Darren McCollester/Getty Images hide caption

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Billionaire businessman Donald Trump has surged to the top of GOP presidential primary polls despite a slew of controversial comments since he launched his campaign in June. Scott Heppell/AP hide caption

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Newly elected Mayor Martin O'Malley (left) waves to supporters in Baltimore in November 1999. Gail Burton/AP hide caption

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