Wisconsin Gov. Scott Walker offers cheese and ice cream to guests in his hospitality room at the Iowa Lincoln Day Dinner in Des Moines on Saturday. Charlie Neibergall/AP hide caption

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Former Florida Gov. Jeb Bush had a tough week with his changing positions on the Iraq War and trying to explain whether he would have authorized it, knowing what we know now. Ross D. Franklin/AP hide caption

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Candidates, and "un-candidates," for the presidency are slicing and dicing campaign-finance law, testing the boundaries of what's legal. TaxCredits.net via Flickr hide caption

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Former President Bill Clinton campaigns before the 2014 elections for former Sen. Mark Pryor, center, and Mike Ross, right, the Democratic candidate for governor. Justin Sullivan/Getty Images hide caption

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Sen. Bernie Sanders, I-Vt., speaks at a rally demanding presidential action to raise the minimum wage to $15 an hour. Sanders will run to Hillary Clinton's left, trying to elevate economic issues. Win McNamee/Getty Images hide caption

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Hillary Clinton's campaign logo was changed Tuesday to show support for same-sex marriage on the day of oral arguments at the Supreme Court. Hillary Clinton campaign hide caption

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Former Secretary of State Hillary Clinton speaks at the Clinton foundation's Clinton Global Initiative conference with her husband, Bill, and daughter, Chelsea, looking on. Michael Loccisano/Getty Images hide caption

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Democratic presidential candidate Hillary Clinton is facing questions about money, access and influence while she was secretary of state. Jacquelyn Martin/AP hide caption

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Hillary Clinton addresses the Pennsylvania AFL-CIO three weeks before the Democratic primary contest against Barack Obama. Seated at right is Pennsylvania AFSCME President Gerald W. McEntee. Charles Dharapak/AP hide caption

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Former Maryland Gov. Martin O'Malley, a Democrat who is considering a 2016 presidential campaign, is interviewed by NPR's Steve Inskeep. Ariel Zambelich/NPR hide caption

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Reporters and campaign staffers rush to their cars to get to Hillary Clinton's first Iowa campaign stop. Tamara Keith/NPR hide caption

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