"We need to fix our dysfunctional political system and get unaccounted money out of it, once and for all, even if that takes a constitutional amendment," Hillary Clinton said at Kirkwood Community College in Iowa Tuesday. Michael B. Thomas/AFP/Getty Images hide caption

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Sen. Rand Paul launched his 2016 presidential campaign Tuesday with a combative message against both Washington and his fellow Republicans, declaring that "we have come to take our country back." Carolyn Kaster/ASSOCIATED PRESS hide caption

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Former Florida Gov. Jeb Bush is one of four "un-candidates" being targeted by liberal groups Campaign Legal Center and Democracy 21. They say the politicians have crossed the line into candidacy based on their activities in recent months. Scott Olson/Getty Images hide caption

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Would-be presidential candidates are ditching "testing the waters" and "exploratory committees" to hold onto unlimited and undisclosed cash for longer. Mark Wilson/Getty Images hide caption

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Hillary Clinton speaks to the media after keynoting a Women's Empowerment Event at the United Nations on Tuesday in New York City. Clinton answered questions about recent allegations of an improperly used email account during her tenure as secretary of state. Yana Paskova/Getty Images hide caption

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Then-U.S. Secretary of State Hillary Clinton sips tea on Turkish television program "Lets come to be with us" at the US Embassy in Ankara March 7, 2009. AFP/Getty Images hide caption

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The Clinton Foundation has taken contributions, of $1 million to $10 million, from the governments of Kuwait and the United Arab Emirates. The Saudi Arabian government has given as much as $25 million. Julie Jacobson/AP hide caption

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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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