By Kirsten Adshead and Kathryn Watson | Wisconsin Reporter

MADISON — Wisconsin’s independent voters swung widely toward Tammy Baldwin and President Barack Obama, bolstering the Democratic Party’s hopes of winning the state in November, according to a Marquette Law School poll released Wednesday.

In the U.S. Senate race, Baldwin leads Republican Tommy Thompson, 50 percent to 41 percent, among likely voters, according to the poll — flipping the nine-point lead Thompson had last month.

President Barack Obama hasn’t visited Wisconsin since his February trip to Master Lock outside Milwaukee. But his lead here has grown nevertheless, according to polling data released Wednesday. Obama is scheduled to return to Milwaukee on Saturday.

Obama’s lead over GOP presidential candidate Mitt Romney grew from 3 percent last month to 14 percent in September among likely voters, according to the new poll.

“Independents are the group that clearly showed the greatest shift,” said Charles Franklin, the University of Wisconsin-Madison political scientist who directs the Marquette poll series.

In August, Independents preferred Thompson, 47 percent to 37 percent, but chose Baldwin, 50 to 38, this month.

Independents chose Obama over Romney 45 to 43 in August; 53 to 38 in September.

The Marquette poll was taken last Thursday through Sunday, coinciding with the attack in Libya that killed four Americans, including the U.S. ambassador. Likely voter questions involved 601 respondents and had a margin of error of 4.1 percentage points.

Baldwin’s and Obama’s leads in the Marquette poll are significantly larger than in other recent polls, but the trend line for the Democrats, overall, has been positive.

Franklin said the number of self-identified Democrats was higher this month than the annual average for the poll.

If the Marquette poll results are adjusted so that the partisan makeup is adjusted to the annual average, Baldwin’s lead drops to 5 percentage points — 48 to 43 — and Obama’s shrinks to 8 percentage points, 51 to 43.

A new Swing State Poll released Wednesday by Quinnipiac University, the New York Times and CBS News shows the Senate race tied at 47 percent and Obama with a 6-point lead in Wisconsin, 51 percent to 45 percent.

That’s despite the fact that Badger State voters say their families — and the country as a whole — are worse off than they were four years ago.

The country is worse off than it was in 2008 — by a 41-33 percent margin — likely voters in Wisconsin say.

Still, Wisconsin voters who participated in the poll said Obama will do a better job than Romney on the economy, 49 percent to 46 percent, and plan to vote for the incumbent president over Romney, 51 to 45.

The poll questioned 1,485 likely voters surveyed by telephone from Sept. 11-17. That widens the 49-47 overall lead Obama had just weeks earlier Aug. 23, soon after Romney announced that Wisconsin Rep. Paul Ryan was to be his running mate. The margin of error was 2.5 percent.

“For the president to be ahead as he is in states where voters think they’re worse off than they were for years ago is not your normal result,” said Peter Brown, assistant director for the Quinnipiac University Polling Institute. “Most times, if voters think things haven’t gone well, they say, ‘Well, let’s get somebody else.’ But at this point, they’re not saying that.”

“They like (Obama) better,” Brown said.

The lull in the Senate race since the Aug. 14 GOP primary has been noticeable.

Franklin said Baldwin and her supporters have dominated the airwaves over the past month, with essentially  no response from Thompson and his backers.

“This is sort of typical of a period where you have sort of one-side flows of information coming from one campaign and the other not responding, and it’s quite dramatic how much the shift has been over that one-month period,” he said.

Part of the reason for his absence, Thompson said Tuesday, is that his campaign went into the hole about $1 million leading up to the competitive Republican primary. “We’re broke, we have no money,” Thompson said Tuesday.

Up to this point, Thompson has been outspent by the Baldwin campaign and outside interests about five to one.

The Center for Responsive Politics, a nonprofit campaign finance tracker, reports Baldwin and outside groups have spent more than $4 million on ads, most attacking Thompson.

Thompson’s campaign and outsiders have spent $860,059 attacking Baldwin.

He said his campaign has been raising money and traveling the state since the primary, instead of spending money on advertisements. He also got a $1 million infusion  from GOP strategist Karl Rove’s nonprofit organization, Crossroads GPS.

“I feel very good about the position we’re in,” Thompson said. “We have nowhere near the money that Congresswoman Baldwin (has), and we have nowhere near the assets or the cash on hand the Democrats have.”

Baldwin’s campaign said the recent poll results indicate Wisconsinites believe she would fight for the middle class and small-business owners.

“Tommy Thompson has cashed in on his Washington connections with these same Washington special interests, and he will continue working for them, not Wisconsin’s middle class,” the Baldwin campaign said in a statement.

Democratic Party of Wisconsin chair Mike Tate took aim at the Rove ad buy, saying it proves “Thompson is in trouble and his special interest friends in Washington are trying to rescue his falling campaign.”

Campaigns can and will quibble over the accuracy of poll data and its implications.

Still, the money being spent here and the attention the race is drawing is further proof that Democrats and Republicans believe Wisconsin may play an integral role in determining which party wins the White House and U.S. Senate in November.

Ann Romney plans to campaign at Marquette on Thursday, and Obama has scheduled a stop at the Summerfest grounds in Milwaukee on Saturday.

Contact Adshead at kadshead@wisconsinreporter.com