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Last month, the "Ryan bounce" was the big story in the battle for Wisconsin's 10 electoral votes.

This month, it may be the "Obama bounce."

President Barack Obama has opened up a larger lead over Mitt Romney in Wisconsin since the party conventions, according to two new statewide polls.

The surveys diverge substantially over the size of that lead.

Obama leads Romney by six points (51% to 45%) in a poll of 1,485 likely voters taken Sept. 11-17 by Quinnipiac University, the New York Times and CBS.

And the president leads Romney by a much larger margin -- 54% to 40% -- in a poll of 601 likely voters taken Sept. 13-16 by Marquette Law School. That's Obama's biggest lead in Marquette's polling since February.

Two more Wisconsin polls due out this week may tell us whether that double-digit Obama margin in the Marquette survey is an outlier or not. Republicans complained that the poll "over-sampled" Democrats, and even the Obama campaign said it thinks the race is closer than that in Wisconsin and that the President's lead is a narrow one.

But while the two surveys released Thursday disagree on the size of Obama's lead, they agree on the direction of the race since mid-to-late August.

In the Quinnipiac poll, Obama led by two points roughly a month ago and now leads by six. In the Marquette poll, Obama led by three points roughly a month ago and now leads by 14.

Both polls had shown Obama's lead narrowing in August after Romney selected home-state congressman Paul Ryan as his running mate. That Ryan bounce was reflected in multiple Wisconsin surveys.

But these latest polls suggest that a post-convention Obama bounce has wiped out the pre-convention Ryan bounce in Wisconsin, where the two campaigns and outside groups have launched or intensified their television advertising in the past week. Obama plans a campaign rally in Milwaukee Saturday. Ann Romney will campaign in Milwaukee Thursday.

You can see the results of the Quinnipiac survey here. The Marquette results are posted here.

Here's the recent trend in Quinnipiac's polling:

And here's the recent trend in Marquette's polling:

In what other ways do the two polls agree?

Obama enjoys a sizable edge in personal attributes in the eyes of voters. In the Marquette poll, voters' perceptions of Romney continue to be more negative than positive, as they have been all year: 36% view him favorably and 51% view him unfavorably. Romney's numbers were better in the Quinnipiac poll, with voters almost evenly divided among those who view Romney positively and those who view him negatively. But Obama is perceived as being much more understanding of people's problems. In the Quinnipiac poll, 60% said Obama “cares about the needs and problems of people like you,” while 43% said the same of Romney. In the Marquette poll, 64% said Obama is "someone who cares about people like me," while 39% said that was true of Romney.

Only a minority of voters feel the nation is better off than four years ago. But in the Marquette poll, 55% still blame former President Bush for the country's economic problems, compared with 30% who blame Obama. And far more people (47%) expect the economy to get better than expect it to get worse (12%). In the Quinnipiac poll, 57% think Obama's economic policies are either improving the economy now, or will do so if given enough time.

The numbers on Ryan are mixed. He gets modestly positive ratings in the Quinnipiac poll, with 43% having a favorable opinion and 38% an unfavorable one. His numbers are a little worse in the Marquette poll (41% favorable, 41% unfavorable), but 56% rated his selection as good or excellent.

Obama has a big edge among women. In the Marquette poll his advantage is massive (57% to 37%) while in the Quinnipiac poll it's more typical of past polling (55% to 42%). The gender gap is especially huge in the Marquette poll, with Obama winning women by 20 and losing men by 10.

In the Marquette poll, 54% of registered voters approved of Obama's performance in office and 39% disapproved, an improvement over his numbers in previous polls. In the Quinnipiac poll, 51% approved and 46% disapproved.

Both polls were taken before news broke of Romney’s comments at a Florida fundraiser this year, describing the 47% of Americans who don’t pay income taxes as Obama voters who see themselves as victims and expect the government to support them. So it doesn’t provide a measure of the impact of that controversy.

But the Quinnipiac poll does suggest that even before those comments, Romney faced the perception that his agenda favored the affluent.

Asked about the impact of each candidate’s policies, 55% said Romney’s polices would favor the rich, while 10% said the middle class and 1% said the poor; in the case of Obama, 10% said his policies would favor the rich, 34% said the middle class and 26% said the poor.

In two other battleground states polled by Quinnipiac at the same time, Obama leads Romney in Virginia 50% to 46%, and Obama leads Romney in Colorado 48% to 47%.

Voters were fairly evenly divided in the Quinnipiac survey over which candidate would do a better job handling the economy, with 49% saying Obama and 46% saying Romney. But Obama had bigger advantages when voters were asked which candidate would be better on health care, on Medicare, on taxes and on national security. By 53% to 41%, voters said Obama would be better handling an international crisis.

Gov. Scott Walker has a positive approval rating in the Quinnipiac poll, with 52% approving and 44% disapproving of his performance in office; but his approval rating was worse in the Marquette poll, with 46% approving and 50% disapproving.

The margin of error among likely voters in the Quinnipiac poll is plus or minus 2.5 percentage points.

The margin of error among likely voters in the Marquette survey is plus or minus 4.1 percentage points.

In discussing the surprisingly large Obama margin in his survey, Marquette pollster Charles Franklin noted Wednesday that self-identified Democrats outnumbered Republicans by 8 percentage points in the sample (and by 11 once independent voters were prodded into choosing a party preference).

Franklin said the polling sample this time was two points more Democratic and three points less Republican than the average sample in Marquette's 2012 polling. If the sample were adjusted to match the yearlong average partisan makeup, then Obama's lead over Romney would have been eight points instead of 14, he said.

Follow Craig Gilbert on Twitter @WisVoter