Obama supporters react as President Barack Obama was declared the winner Tuesday, during the Nevada State Democratic Party gathering at the Mandalay Bay Resort and Casino in Las Vegas. John Gurzinski/AP hide caption

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President Obama signs the Affordable Care Act in the East Room of the White House on March 23, 2010. Data suggest that racial attitudes of ordinary Americans shape both how they feel about the health care overhaul and how intense those feelings are. Chip Somodevilla/Getty Images hide caption

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In his career, Manning Marable wrote about the struggle for equal rights — and especially the life of Malcolm X. In this file photo from 2001, he posed at his Columbia University office in New York. Mario Tama/Getty Images hide caption

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