President Obama has established a substantial lead against Republican challenger Mitt Romney in Minnesota but remains under the critical 50 percent mark and trails Romney among independent voters, according to a Star Tribune Minnesota Poll.

The poll shows Obama drawing 48 percent of likely voters to Romney's 40 percent. Part of Obama's advantage comes from a yawning gender gap in his favor. Romney has a slight edge among men, but the president leads among women voters by more than 20 percentage points.

Obama wallops Romney in Hennepin and Ramsey Counties, but that support falls off quickly in the outer suburbs and exurbs, where Romney leads. Obama also racks up big support in the northeastern part of the state, including Duluth, leading Romney 54 to 33 percent, but Romney bests Obama in southwestern Minnesota, 42 to 37 percent. That part of the state also has the most undecided voters -- 15 percent.

Statewide, Libertarian Party candidate Gary Johnson draws 5 percent, with 7 percent undecided.

Obama's lead helps explain why, for the first time in more than a decade, Minnesota is not on the presidential campaigns' target lists. No poll this year has shown Romney topping Obama in Minnesota and some polls show the president with a double-digit advantage.

The poll, conducted Sept. 17-19, interviewed 800 likely voters and has a margin of error of plus or minus 3.5 percentage points.

If 2012 were like other recent years, Romney's advantage among independents, nearly 60 percent of whom give Obama low job approval ratings, would give Republicans reason to press the state for its 10 electoral votes. But this year, Romney has a slim presence in the state as he fights for the votes of Minnesota's neighbors.

The Star Tribune Minnesota Poll comes after a rough patch for Romney. On the heels of a Democratic convention that gave Obama a lift, it was disclosed that Romney had called Obama supporters, which he pegged at 47 percent of the country, "victims."

Republicans had hoped Romney's pick of Wisconsin U.S. Rep. Paul Ryan would help him win over his Minnesota neighbors. But the poll shows no Ryan groundswell. Minnesotans were equally divided in their feelings toward Ryan. A quarter of Minnesotans said they either didn't recognize his name or were neutral about him.

Economy is the top issue

Minnesota voters like Obama a bit more than Romney, but neither is terribly popular. Obama is viewed favorably by 45 percent, while Romney is viewed that way by 37 percent.

But 40 percent said they felt unfavorably about Obama, while 43 percent felt the same way about Romney. Voters were evenly split on how they judge Obama's job performance -- 48 percent approved marks and 47 percent disapproved.

Candidates who want to firm up their support would do well to tell voters what they would do about the issue that concerns them most: Jobs and an economy that creates them. After the Great Recession and a flabby recovery, 48 percent of likely voters in the poll say jobs and the economy will drive their vote. Taxes, government spending and the national debt came in a distant second at 23 percent, with health care at 21 percent.

While talk of national security and social issues such as abortion and same-sex marriage have gotten lots of air time, they rank low on voters' priority list. Only 6 percent said they would vote based on national security and a mere 1 percent said it would be dictated by social issues.

Janet Schneider, a St. Paul Democrat, is one of those worried about jobs and health care. She's 69 and is looking for a part-time job to make ends meet. But she thinks Obama deserves another shot.

"I think people haven't given him a chance to get our country back where we want it to be," she said.

Others, such as Sandra Revner, a retired purchasing agent from Arlington, in Sibley County, considers Obama an elitist who failed to fulfill his promises and engineered a health care overhaul she despises. She'll vote for Romney, but says "it's less liking him so much as disliking Obama."

Dan Rossiter, a New Brighton high school teacher, said he is disappointed in both sides. "I just think they need to grow up and learn to work together," he said. A lifelong Democrat, Rossiter says he'll still vote for Obama.

"I don't think that things have gotten better but I don't think it is necessarily his fault," Rossiter said. "I think he has tried to look out for the middle class."

But Mark Juven, an independent from Moorhead, says no more second chances.

"Obama is trying so hard. I really do believe he is," said Juven, a pharmaceutical sales representative. But, he said, the president has not completed the job and it's time to give Romney a turn. Juven hopes the Republican's business background will help him wrestle the deficit under control.

The poll included 41 percent self-identifying Democrats, 31 percent Independents and 28 percent Republicans. Brad Coker, managing director of Mason-Dixon Polling & Research, which conducted the poll for the Star Tribune, said those numbers are consistent with what he has seen over the years. Minnesota does not have voter registration by party and the state's party self-identification fluctuates over time.

Rachel E. Stassen-Berger • Twitter: @rachelsb