ATLANTA, Georgia (CNN) -- Hillary Clinton and Barack Obama may be competing in the South Carolina Democratic Primary Saturday, but they're also vying for the top prize in another contest: The Oppression Sweepstakes. That's how Michael Jelani Cobb, an African-American historian, describes the surge of venom that recently erupted between the Clinton and Obama camps. The sweepstakes kicks in when two excluded groups find themselves competing for the same prize. He says that took place in the 19th century when the abolitionist, Frederick Douglass and his ally, women's rights' activist, Elizabeth Cady Stanton, argued over what group should first be...
