Across The Divide: How Barack Obama Is Shaking Up Old Assumptions

msnbc.msn.com — Obama faces many challenges in what he calls his "improbable candidacy," but few are as complex or emotional as the politics of race. Racial politics are a key source of his campaign's energy, but they could also be his undoing. Obama wants to be the nation's first black president. One eye-catching measure of Obama's broad support is his