Another key for Bush: He won back his party's core. Bush lost the New Hampshire's leadoff GOP primary Feb. 1 in part because self-described Republicans only narrowly favored him over McCain, who has drawn his strongest support from independents and crossover Democrats. But in South Carolina, Bush took roughly 70 percent of those who call themselves Republican.

The party faithful offset a slightly larger than usual turnout of Democrats and independents in the South Carolina GOP's open primary, according to exit polling by Voter News Service for The Associated Press and television networks. Democrats were 9 percent of the electorate, compared to 5 percent in the 1996 South Carolina GOP primary, and 80 percent of them backed McCain, who also won 60 percent of independents.

Bush runs with strong backing from the Republican establishment. While a majority of exit poll respondents said they preferred a candidate who is not tied to party leaders, Bush won three quarters of the remainder who said they favor someone loyal to the GOP.

The survey indicated that as the campaign turned sharply negative after the Feb. 1 New Hampshire primary, Bush's attacks hurt McCain. They also suggest the Arizona senator may have hurt himself with attacks on Bush.

In New Hampshire, just 15 percent of voters viewed McCain unfavorably; that increased to 30 percent in South Carolina. Bush's favorable rating rose from 60 percent to 73 percent. And more voters said McCain attacked Bush unfairly than the other way around.

"I was leaning to McCain until he compared Bush to Bill Clinton, and that poisoned him for me," Willis Cox, of Florence said. "They were both negative, but no stone was thrown like that."

The issues McCain hoped would sway independents and Democrats failed to register strongly enough to overcome the state's conservative, establishment tilt. Only 1 in 20 said campaign finance reform, a centerpiece of McCain's message, was the top issue.

Bush succeeded in neutralizing McCain's emphasis on that issue with his new line of attack in the past week, accusing McCain of saying one thing but doing another when it comes to campaign finance. More than 4 in 10 voters agreed with Bush on that.

The exit poll found that more than a third of voters said moral values was the most important issue for them, and Bush won more than half of them. He also won 8 in 10 of those who said they voted based on the candidate who best represented their conservative values.

Nearly two-thirds of voters Saturday called themselves conservative, and Bush won more than 6 in 10 of them. Bush ran especially strongly among those who called themselves "very conservative." A third called themselves part of the religious right, and Bush won two-thirds of their votes. Bush also drew strong support from abortion foes, who made up 60 percent of the electorate.

Among those who did not call themselves part of the religious right, a majority supported McCain.

After losing decisively to McCain in New Hampshire, Bush changed his message to "reformer with results" -- and it apparently worked. Six in 10 voters said Bush is a real reformer, while little more than half considered that term fit McCain.

Political analysts said McCain erred by airing ads that compared Bush to President Clinton. A quarter of those who voted for McCain said he unfairly attacked Bush. Just 15 percent of Bush voters said they thought his attacks against McCain were unfair.

"That probably helped deep six him in the last week," said Neal Thigpen, a Francis Marion University political scientist and McCain supporter.

The poll results were from interviews of 2,078 voters in 40 precincts around South Carolina. The margin of sampling error was plus of minus 3 percentage points, larger for subgroups.