Barack Obama has opened up an 11-point edge on John McCain in Minnesota, according to a new Quinnipiac University poll. Prior to last week’s debate, a similar survey determined that the Democrat held an eight-point lead.

The poll looked at three other battleground states pre- and post-debate and found Obama enjoying similarly strong margins. In Colorado the Democrat has opened up a nine-point edge, while in Wisconsin his lead doubled to 17 points following last week’s debate. The Illinois senator also holds a 16-point lead in Michigan, where the McCain campaign recently pulled up stakes, all but conceding what was expected to be a key battleground state.

“Sen. Obama’s leads in these four battleground states are as large as they have been the entire campaign,” said Peter Brown, assistant director of the Quinnipiac University Polling Institute, in a statement accompanying the survey results. “Those margins may be insurmountable barring a reversal that has never been seen before in the modern era in which polling monitors public opinion throughout the campaign.”

The Quinnipiac University poll also found Minnesota’s U.S. Senate race to be a dead heat. Democrat Al Franken leads incumbent Norm Coleman by a statistically insignificant two-point margin, 38-36 percent, with Independence Party candidate Dean Barkley garnering support from 18 percent of those surveyed.

Voters in the four states registered remarkably similar opinions about the presidential contest. Each survey found that the economy is the most important issue facing voters and that Barack Obama is the candidate best equipped to deal with the current crisis (49-34 percent in Minnesota). Voters in the four states were also in agreement that Sarah Palin is not qualified to be vice president (47-43 percent in Minnesota) and that Obama won last week’s debate (57-22 percent in Minnesota).