Republican presidential candidate Mitt Romney greets supporters in Aston, Pa., on April 23. Jessica Kourkounis/Getty Images hide caption

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President Obama boards Air Force One at Andrews Air Force Base in Maryland, en route to Florida, on April 10. Whenever a president runs for re-election, his travel tends to become a political issue. Cliff Owen/AP hide caption

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Mitt Romney may like to say the president is out of ideas, but Obama's re-election campaign is definitely not out of money. Chip Somodevilla/Getty Images hide caption

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Selina Gray of Sanford, Fla., shows her sign at a rally protesting the death of Trayvon Martin, the unarmed teen shot by a neighborhood watch volunteer. Authorities have cited the state's "stand your ground" law as a reason charges have not been filed in Martin's death. Julie Fletcher/AP hide caption

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Foster Friess introduces Rick Santorum at the 2012 CPAC Conference in Washington, D.C., on Feb. 10 wearing a sweater vest embroidered with the candidate's name. Ron Sachs/CNP DPA/Landov hide caption

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Sheldon Adelson speaks at the 2008 "Facing Tomorrow" Presidential Conference in Jerusalem. David Silverman/Getty Images hide caption

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The superPAC Campaign for Primary Accountability is taking aim at Alabama Republican Rep. Spencer Bachus and other congressional incumbents. YouTube hide caption

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