Margaret Sanger appears before a Senate committee for federal birth-control legislation in Washington, D.C., on March 1, 1934, arguing that federal courts be given the right to discuss contraceptive methods with their patients. Anonymous/AP hide caption

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President George W. Bush (center) surveys the devastation in New Orleans with (from left to right) Vice Adm. Thad Allen, Louisiana Gov. Kathleen Blanco, Mayor Ray Nagin and Lt. Gen. Russel Honore on Sept. 12, 2005, two weeks after Hurricane Katrina slammed into the Gulf Coast. Jim Watson/AFP/Getty Images hide caption

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Mitt Romney peers over the podium at guests being pointed out by his wife, Ann, during an event at which Donald Trump endorsed Romney in 2012. Ethan Miller/Getty Images hide caption

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Sen. Bernie Sanders in his office in 1981, shortly after becoming mayor of Burlington, Vt. He once said his tenure as a socialist mayor is evidence people are willing to accept radical change. Donna Light/AP hide caption

itoggle caption Donna Light/AP