WASHINGTON  New York Sen. Hillary Rodham Clinton has significantly widened her lead over Illinois Sen. Barack Obama for the Democratic presidential nomination in the wake of a dispute over handling foreign policy, a USA TODAY/Gallup Poll finds.

The survey, taken Friday through Sunday, puts Clinton at 48% — up 8 percentage points from three weeks ago — and Obama at 26%, down 2 points. Among Democrats and independents who "lean" Democratic, former North Carolina senator John Edwards is at 12%.

POLL RESULTS: The 2008 race

The 22-point gap between the two leaders is nearly double the margin found in the July 12-15 poll.

"People are seeing her as the one ready to be president," says Mark Penn, Clinton's chief strategist, a perception he says was "accelerated" by the recent debate.

Bill Burton, Obama's spokesman, dismisses the findings. "National polls may go up and down before people actually start voting, but their irrelevance will not," he says.

Among Republicans, the race was stable: Former New York mayor Rudy Giuliani at 33%, former Tennessee senator Fred Thompson at 21%, Arizona Sen. John McCain at 16% and former Massachusetts governor Mitt Romney at 8%.

The Democratic race is much closer in the states where opening contests will be held and campaigning already is fierce. Clinton and Edwards are essentially tied in Iowa, according to the three most recent statewide polls aggregated by the political website RealClearPolitics.com. She holds a small lead over Obama in New Hampshire.

"She's a known quantity, and she does have significant strengths," says Democratic strategist Anita Dunn, who isn't affiliated with a campaign. "But where he has started to fill in some of the blanks, he's very competitive."

Still, the new poll seems to reflect some success by Clinton in portraying her chief rival as inexperienced and naive on foreign policy. In a debate sponsored by CNN and YouTube two weeks ago, Obama said he would meet as president with such rogue leaders as Mahmoud Ahmadinejad of Iran and Hugo Chávez of Venezuela.

Clinton refused to make that pledge, saying, "I don't want to be used for propaganda purposes."

Both campaigns spotlighted the exchange afterward.

In the survey, Democrats and Democratic-leaning independents by overwhelming margins say Clinton would do a better job as president than Obama in handling terrorism, the Iraq war and relations with unfriendly nations.

If the nomination comes down between the two, Clinton was preferred over Obama 59%-36%.

Also in the poll, President Bush's approval rating ticked up to 34%, still dismal but better than his low of 29% in July.

And Congress? The approval rating for congressional Republicans sank to 29%, for congressional Democrats to 37% — both new lows in the eight years since the question was first asked.

The survey of 1,012 adults has an error margin of +/- 3 points for the full sample, 5 points for the Republican and Democratic subsamples.

Enlarge By Charles Rex Arbogast, AP Democratic presidential hopefuls, Sen. Barack Obama, D-Ill., right, applauds with Sen. Hillary Rodham Clinton, D-N.Y., after they participated in the Yearly Kos Convention's Presidential Leadership Forum in Chicago.