New York Sen. Hillary Rodham Clinton has regained a double-digit lead over Illinois Sen. Barack Obama in the USA TODAY/Gallup Poll two weeks after the survey found the Democratic presidential rivals essentially tied.
Among Republicans, former New York City mayor Rudy Giuliani remains ahead, but former Tennessee senator Fred Thompson, who hasn't formally entered the race, for the first time edges into second place over Arizona Sen. John McCain.
The results show a Republican race that could be roiled by Thompson, who is targeting conservatives unsatisfied with their choices in the field so far. He is costing Giuliani most: A third of Thompson's supporters say they would otherwise back the former mayor.
The Democratic contest generally has been stable, though a USA TODAY Poll taken June 1-3 had shown Obama 1 percentage point ahead of Clinton, 30%-29%. In the new survey, Clinton leads Obama 33%-21% if former vice president Al Gore — who has neither entered the race nor ruled it out — is included among the candidates.
She leads by 39%-26% if Gore isn't included. Former North Carolina senator John Edwards is then third at 13%.
"There have been 500 stories and 500 polls, but actually little has changed in this race," says Mark Penn, Clinton's chief strategist. "She has a consistently strong lead that is holding up over time."
The new poll includes 334 Democrats and 182 independents who lean Democratic. Penn says including independents contributes to a survey's volatility because those voters are less committed to a candidate as well as less likely to vote in party primaries.
Frank Newport, editor in chief of the Gallup Poll, said the previous poll "either picked up a short-term change or … was a function of unusual sampling, which happened to pick up Democrats who were more pro-Obama than the underlying population."
The NBC News/Wall Street Journal poll and the Quinnipiac poll last week reported findings similar to the new Gallup survey. Both showed Clinton with a 14-point lead and Thompson tied with or ahead of McCain.
The USA TODAY Poll, taken last Monday through Thursday, has a margin of error of +/—5 percentage points among the subsample of 393 Republicans or Republican-leaning independents and the 516 Democrats or Democratic-leaning independents.
On the GOP side, Thompson's rise is bad news for his major rivals.
Giuliani leads the field at 28%, down 4 points from two weeks earlier. Thompson is second at 19%, up 8 points. McCain is at 18%, 1 point lower. Former Massachusetts governor Mitt Romney is fourth at 7%, down 5 points.
"It's a long campaign and it's only June, and these polls are going to move around," says Terry Nelson, McCain's campaign manager. "There's a lot of campaign for folks still to have and still a lot of issues to be debated." Most Republicans aren't firmly settled on any contender, he says.
He predicts that Thompson will get "a bump" when he formally announces his candidacy, likely next month.
Although Thompson's lead over McCain isn't wide enough to be statistically significant, it underscores the political problems plaguing the Arizona senator. Six months ago, he was tied with Giuliani at the top of the field.
The next benchmark: fundraising reports for the second quarter of the year, due next month. McCain lagged behind Romney and Giuliani in money raised during the first quarter.
When Thompson's supporters were asked their second choice, 34% picked Giuliani; 16%, Romney; and 14%, McCain.
If the GOP contest came down to Giuliani or Thompson, Republicans and Republican-leaning independents chose Giuliani, 53%-41%.
If the Democratic contest came down to Clinton or Obama, Democrats and Democratic-leaning independents chose Clinton, 53%-42%.