Democrat presidential nominee Barack Obama has widened his lead over Republican John McCain in Wisconsin by 17 points, according to the latest poll of likely voters released today by Quinnipiac University, in partnership with The Wall Street Journal and washingtonpost.com.

In the aftermath of last week's town hall-style debate, Obama extended his lead in the Badger state to 54 to 37 percent.

Obama is over the 50-percent mark in the key battleground states of Colorado, Michigan, Minnesota and Wisconsin, and for the first time leads or ties McCain among white voters in all four states, according to four simultaneous Quinnipiac University polls of likely voters.

By wide margins, voters in each state say Obama understands the economy better than McCain. By larger margins, voters say McCain better understands foreign policy.

Obama has caught or passed McCain among men voters in all four states for the first time.

"Sen. Obama's leads in these four battleground states are as large as they have been the entire campaign. 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," said Peter Brown, assistant director of the Quinnipiac University Polling Institute.

"Even white men favor Barack Obama in Wisconsin where his debate performance and the crumbling economy sparked a doubling of his lead over John McCain. It is one of the few battleground states where Obama has a substantial lead among blue collar voters and Catholics as well as white men and women," said Clay Richards, assistant director of the Quinnipiac University Polling Institute.

"The only possible bright spot for Sen. McCain - and you would need Mary Poppins to find it in these numbers - is that he is holding roughly the same portion of the Republican vote. But McCain's support among independent voters, a group he says are key to winning the White House, has collapsed," Brown said. "Any realistic chance of McCain coming from behind depends on scoring a knockout in this week's last debate. But given that he has been judged by the electorate to have lost both of the previous face-offs, that would seem to be a very tall order. Obama's surge comes from voters saying by wide margins that he better understands the economy. Moreover, about that many more say McCain has not shown effective leadership on the economy than has done so."

The final debate between the two candidates will take place Wednesday night. Earlier this week, McCain vowed to "whip his you know what" in the debate.

To read more about the two candidates' economic plans, visit www.biztimes.com.