ST. PAUL, Minn. - A new statewide poll that surveyed likely voters twice in a week's time showed surging support for Democratic presidential candidate Barack Obama in Minnesota.

The Minnesota Public Radio/University of Minnesota Humphrey Institute poll sampled 346 likely voters between last Monday and last Wednesday, in advance of Thursday's vice presidential debate and congressional approval of the Wall Street bailout; and then sampled a separate group of 418 likely voters over the weekend.

Obama shot to a 14-point lead with the support of 54 percent of those polled over the weekend, compared to 40 percent for Republican John McCain. The margin of sampling error was plus or minus 4.8 percentage points.

It was a dramatic upswing for Obama over the survey of a few days earlier, which found 47 percent supported Obama to 43 percent for McCain - within the margin of error of 5.3 percentage points.

University of Minnesota political scientist Larry Jacobs said the troubled economy was the main reason for Obama's spike in support. Voter confidence in how Obama would handle the financial crisis went from a three-point margin over McCain to a 14-point margin.

Jacobs said the second poll also found that more people were impressed with Delaware Sen. Joe Biden than with Alaska Gov. Sarah Palin in the vice presidential debate.

The numbers in the second MPR/University of Minnesota poll tracked pretty closely with those in a Star Tribune poll published over the weekend, which found Obama leading McCain 55 percent to 37 percent. That, too, was a significant leap for Obama after a mid-September Star Tribune poll that showed the two candidates deadlocked.

Jeff Blodgett, Obama's Minnesota director, said the campaign isn't putting much stock in any one poll. But he said the latest numbers aren't a big surprise.

"As they tune in and as they are concerned about the economy, they're asking the question 'Which candidate is better able to handle the economy going forward and to get us out of this economic mess?"' Blodgett said.

Ben Golnik, McCain's regional campaign manager, suggested that the poll sampled too many Democrats after the debate - but agreed with the finding that one in five voters could change their minds before Election Day.

Those are the voters the campaign will target, he said, noting that McCain is scheduled to campaign in the Minneapolis suburb of Lakeville on Friday. Michelle Obama, the candidate's wife, is scheduled to campaign in Minnesota on Monday.