WASHINGTON Republican John McCain holds a 6-point lead over rival Mike Huckabee in South Carolina three days before the state's crucial presidential nominating contest, according to a Reuters/C-SPAN/Zogby poll released on Wednesday.
McCain, an Arizona senator, leads the former Arkansas governor by 29 percent to 23 percent. Former Massachusetts Gov. Mitt Romney was in third place with 13 percent.
South Carolina's Republican primary on Saturday is the next battleground as both parties choose candidates for November's election to succeed President George W. Bush. Nevada also holds Republican and Democratic nominating contests on that day.
The polling was conducted Sunday through Tuesday, before Romney's breakthrough win on Tuesday night in Michigan scrambled a chaotic Republican race with no clear front-runner.
The wildly fluctuating Republican race has produced three winners in the first three significant contests -- Huckabee in Iowa on January 3, McCain in New Hampshire last week and Romney in Michigan.
"Romney's win in Michigan will probably cut into McCain's lead," pollster John Zogby said. McCain's advantage had been shrinking during the first days of polling and already was down from an initial double-digits, he said.
The rolling tracking poll of 813 likely voters in South Carolina's Republican primary had a margin of error of 3.4 percentage points.
In fourth place among Republicans was former Tennessee Sen. Fred Thompson. Texas Rep. Ron Paul trailed with 6 percent and former New York Mayor Rudy Giuliani had 5 percent.
Giuliani, whose one-time lead in national opinion polls has vanished, bypassed the early voting states to concentrate on the January 29 Florida primary and the February 5 "Super Tuesday" round of 22 contests.
But Romney's win in Michigan was good news for Giuliani, ensuring the race would not have a dominant figure at the top of the field before he can get in the game.
Huckabee and McCain headed to South Carolina on Tuesday before the Michigan results were even tallied. Romney will make his way there on Wednesday.
Thompson, who finished third in Iowa and has staked his campaign on a strong finish in South Carolina, could help McCain in the state by robbing some of the most conservative voters from Huckabee, Zogby said.
The poll found Huckabee led among voters who described themselves as very conservative with 33 percent, but Thompson was second with 21 percent and McCain third with 17 percent.
About 10 percent of the poll's respondents said they had not decided on a candidate yet, leaving plenty of room for swings in momentum.
This is the first day of the rolling tracking poll in South Carolina, which will continue until Saturday's voting. In a rolling poll, the most recent day's results are added while the oldest day's results are dropped in order to track changing momentum.
(Editing by Chris Wilson)
(For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at blogs.reuters.com/trail08/)