To move closer to clinching the Democratic presidential nomination, the Illinois senator will need a broader coalition of independents, young people and affluent whites if he takes more states on Super Tuesday, when 22 states vote on Feb. 5, The Christian Science Monitor reported Sunday.
In South Carolina, where more than half the voters were black, Obama defeated his closest rival Sen. Hillary Clinton, D-N.Y., 55 percent to 27 percent.
"Obama went into South Carolina as a candidate speaking to independents, to whites, speaking to America across the divides -- that was kind of his magic," said Lawrence Jacobs, a political scientist at the University of Minnesota.
But if his showing is perceived as racially polarized, "it could well be that South Carolina is a race that really winds up narrowing a very broadly appealing campaign," he said.
Others say Obama's greatest obstacle will be gaining the support of traditional Democrats with whom Clinton is popular.
"He needs to run better among older voters, more blue-collar and middle-class voters, and more downscale white voters," says Philip Klinkner, a government professor at Hamilton College. "That's where he's losing."