Republican Ted Cruz makes a campaign stop at the Bravo Cafe Monday in Osceola, Ind. The Hoosier State might be Cruz's last chance to stop Donald Trump from getting the nomination. Joe Raedle/Getty Images hide caption

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Candidate for U.S. Senate Katie McGinty, D-Pa., shakes hands with attendees as she arrives for her roundtable discussion with seniors at the Philadelphia Federation of Teachers in Philadelphia last week. Bill Clark/CQ-Roll Call Group hide caption

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Democratic presidential candidate Hillary Clinton speaks at a Las Vegas high school last Friday. Justin Sullivan/Getty Images hide caption

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Hillary Clinton Hitches Her Health Care Wagon To Obamacare

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Former first lady Barbara Bush, mother of Republican presidential candidate Jeb Bush, campaigns with her son at a town hall meeting at West Running Brook Middle School in Derry, N.H. Jacquelyn Martin/AP hide caption

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Bernie Sanders, Hillary Clinton, center, and Martin O'Malley on stage at the Democratic presidential primary debate Saturday at Saint Anselm College in Manchester, N.H. Jim Cole/AP hide caption

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Buddie, the mascot for the pro-marijuana legalization group ResponsibleOhio, waits on a sidewalk to greet passing college students during a promotional tour at Miami University of Ohio last month. John Minchillo/AP hide caption

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Hillary Clinton participated in 25 primary debates during her 2008 campaign — experience that should serve her well on Tuesday night. But she still has to appear likable and at ease on stage this time. Matt Rourke/AP hide caption

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Harvard Law professor Lawrence Lessig lists Facebook's Sheryl Sandberg and former Daily Show host Jon Stewart as possible running mates among those from whom visitors to his website can choose. Fadi Alassaad/Reuters/Landov hide caption

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