COLUMBIA — White voters accounted for the bulk of people casting ballots in South Carolina's presidential contest, and three-quarters of them supported Republican John McCain, but a core of white Democrats in this GOP stronghold voted for president-elect Barack Obama.

An exit poll by The Associated Press sheds a little more light on that outnumbered group: A majority were college-educated, higher-income Democrats who chose their candidate months ago. Three in five were women and nearly all disapproved of the way President Bush has handled his job.

Among this group are de Rosset and Felicity Myers of Columbia, who arrived at their precinct early to vote for Obama.

"The economy, the war, the Bush administration. Need I say more?" de Rosset Myers, a 59-year-old clinical psychologist, said about his decision.

Felicity Myers said health care was her top issue. "I believe in Obama's values, and I believe he would be good for the country," said the 49-year-old health care administrator.

Among white voters supporting Obama, more than two-thirds earned more than $50,000 a year. Fewer than one in five voters were considered highly educated, meaning they were educated beyond one college degree, but they accounted for the biggest chunk of Obama's white supporters.

One in five white voters supporting Obama in South Carolina, where racial tensions still run high, said race was a factor in their decision, compared with about one-third of McCain's voters.

Michael Culler, who voted in Charleston, said he hopes Obama's win improves race relations.

"You can only hope that not only on the national stage but on the local stage as well there is impact," said the 37-year-old business management consultant. "You can always hope that's going to make a difference and improve where we are today."

More than half of Obama's white supporters identified themselves as moderate.

As a group, they did not vote a straight Democratic ticket. More than a quarter of white voters who backed Obama also checked the box for GOP Sen. Lindsey Graham, who easily kept his seat over Democratic challenger Bob Conley.

Overall, white voters' support for Obama on Tuesday represented no significant change from their support for Democrats in the last four presidential contests in South Carolina.

The case is different for black voters. As expected, nearly all black voters in South Carolina cast their ballot for Obama, surpassing their support for previous Democratic presidential candidates.

However, the black vote in South Carolina, as a proportion of the overall vote, was similar to previous elections.

Nationwide, voters under 30 supported Obama by a more than 2-1 ratio. That was not the case in South Carolina, where just over half of young voters supported Obama.

Among white voters in South Carolina, most of Obama's support came from ages 30 to 64.

The exit poll of 1,163 South Carolina voters was conducted for AP by Edison Media Research and Mitofsky International in a random sample of 20 precincts statewide. Results were subject to sampling error of plus or minus 4 percentage points, higher for subgroups.