Democratic presidential candidate Barack Obama has opened up a commanding lead in Minnesota over Republican John McCain, according to a new Star Tribune Minnesota Poll.

The poll, conducted last week among 1,084 likely voters, found that 55 percent support Obama, while 37 percent back McCain.

That's a huge difference from the last Minnesota Poll, conducted in September, which showed the race dead even, with each candidate backed by 45 percent of likely voters. The new poll shows that Obama's surge in the state can be attributed to voters' belief in his ability to deal with the nation's worsening economy, his performance in the first presidential debate and an increase in the number of Minnesotans who call themselves Democrats.

Obama appears comfortably ahead among men, women, and voters of all ages and educational attainment.

The poll's findings come at a time when polls in several other battleground states and nationally are showing a sudden and significant shift to Obama. Gallup's daily national tracking poll released Friday showed Obama leading McCain by 7 percentage points.

Statewide polls conducted last week show Obama overtaking McCain in such key battleground states as Ohio, Virginia and Florida. In Florida, for example, the last four polls have shown Obama with leads of between three and eight percentage points; in the weeks prior, Obama trailed by as many as 10 points.

In Minnesota, for decades the most reliably Democratic state in presidential elections, a CNN/Time poll conducted last weekend showed Obama ahead, 54 percent to 43 percent. However, a Survey USA poll conducted last week showed McCain ahead among the state's likely voters, 47 percent to 46 percent.

Ben Golnik, Upper Midwest coordinator the McCain campaign, said of the Star Tribune poll: "Clearly this poll is out of whack from every other recent public poll, including the Survey USA poll from two days ago. ... The explanation is simple: When a poll only includes one-quarter Republicans and a higher number of both independents and Democrats, these results are to be expected."

Jeff Blodgett, who heads the Obama campaign in Minnesota, said, "I don't know what to make of all these polls that have us up and down and at the same time. I don't spend much time thinking about them. We do feel the voters are coming our way because of the economy.''

Economy central

Two keys to understanding Obama's apparent strength in Minnesota can be found in an abrupt change in likely voters' party affiliations and their near-universal revulsion with the way things currently are going in the United States.

Forty-two percent of respondents identified themselves as Democrats in the latest poll, up from 34 percent a month ago. In the same period, the percentage of Minnesotans calling themselves Republicans has dropped from 31 percent to 26 percent.

Larry Hugick, chairman of Princeton Survey Research Associates International, the Star Tribune's polling firm, has studied party identification shifts in presidential years and found that it moves in concert with the results of the candidate horse race. In a study that he and an associate conducted during the 2004 presidential race, they found that 18 percent of registered voters changed their self-described party affiliation between September and October 2004.

At the same time, in the latest poll, 80 percent of Minnesotans believe the nation has "gotten seriously off on the wrong track," the harshest assessment they have had of the general state of the nation during the Bush administration.