Children release 95 balloons to mark Nelson Mandela's upcoming birthday outside the Mediclinic Heart Hospital where Mandela is being treated for a recurring lung infection in Pretoria, South Africa. Chip Somodevilla/Getty Images hide caption

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Former President George W. Bush and his successor, President Obama, at the April 25 dedication of Bush's library on the campus of Southern Methodist University in Dallas. Larry W. Smith /EPA /LANDOV hide caption

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A sea of self-motivated individuals or a web of interdependent talents? Both, of course. Jewel Samad/AFP/Getty Images hide caption

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Allan Lichtman, a professor at American University, discusses his 13 keys to a successful election campaign on April 13 in his office in Washington, D.C. Paul J. Richards/AFP/Getty Images hide caption

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President Obama and GOP presidential nominee Mitt Romney walk away after they greet each other at the end of the third presidential debate in Boca Raton, Fla., on Monday. Saul Loeb/AFP/Getty Images hide caption

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President Obama speaks at a rally Thursday in Manchester, N.H. Utah's Salt Lake Tribune on Friday endorsed Obama for president. Brendan Smialowski/AFP/Getty Images hide caption

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