Former Alaska Gov. Sarah Palin, center, visits a Civil War-era cemetery, Tuesday, May 31, 2011, at Gettysburg National Military Park. Timothy Jacobsen/AP hide caption

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Asma Jehangir, a human rights advocate and lawyer in Lahore, Pakistan, is an outspoken critic of the military. Jim Wildman/NPR hide caption

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President Obama, with Facebook CEO Mark Zuckerberg, speaks during a town hall meeting April 20 at Facebook headquarters in Palo Alto, Calif. Mandel Ngan/AFP/Getty Images hide caption

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Former Alaska Gov. Sarah Palin greets some of the thousands of motorcycle enthusiasts and military veterans participating in the Rolling Thunder rally on Sunday. Chip Somodevilla/Getty Images hide caption

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Corn is big business in Iowa, which has usually made anything but support for ethanol subsidies off-limits for presidential hopefuls. Steve Pope/AP hide caption

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Sen. Rand Paul (R-KY) speaks during a Tea Party Town Hall meeting in February at the National Press Club in Washington. The freshman lawmaker is being hailed by civil libertarians for putting privacy concerns over the Patriot Act back in the spotlight. Alex Wong/Getty Images hide caption

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