U.S. Sen. Al Franken is leading Republican challenger Mike McFadden by 48 to 39 percent, though Franken's advantage appears to have slipped in recent weeks, according to a Star Tribune Minnesota Poll.

McFadden had been down by 13 percentage points, according to the previous Minnesota Poll taken in September. He continues to run far ahead of Franken in outer suburbs and has nearly twice Franken's support among independents, who favor the challenger 46 percent to 27 percent.

In contrast, Franken is showing strong support in Hennepin and Ramsey counties, and across northern Minnesota.

The poll, conducted by the independent polling firm Mason-Dixon for the Star Tribune, interviewed 800 likely Minnesota voters Oct. 20-22 and has a margin of sampling error of 3.5 percentage points, plus or minus. About 9 percent of voters remain undecided as the Nov. 4 election approaches, while 3 percent are opting for Independence Party candidate Steve Carlson, who has run a nominal campaign.

Franken stopped short of calling the numbers encouraging or discouraging, saying simply, "Polls are polls."

"I just feel like I need to work as hard as I can and I'm not going to let up," he said. "We're just working on turning people out" to vote. "A lot of this means that we have to turn people out."

McFadden reflected a similar sentiment. "I don't really focus on polls," McFadden said. "The more opportunity I have to get in front of people, the more people we get into our camp. I'm very, very encouraged and enthused with the momentum of the campaign. I just feel it, just being out there day in and day out."

The latest Minnesota poll shows some new shifts between the candidates.

For example, Franken appears to have erased a 20-plus point lead that McFadden held last month in northern Minnesota, according to the previous Star Tribune poll. Franken now has a 45 percent to 34 percent advantage in the region. The Iron Range has become politically volatile in recent elections over issues like the proposed PolyMet copper-nickel mining project that has divided organized labor and environmentalists; it is also home to a hotly contested Eighth Congressional District race.

Meanwhile, McFadden has gained ground in southern Minnesota, where he now trails Franken by only a couple of percentage points.

Throughout his campaign, McFadden has worked hard to link Franken to the low approval ratings of President Obama, emphasizing repeatedly that Franken votes with the president 97 percent of the time. But that criticism does not appear to have hurt Franken's job-approval rating, which has risen slightly, from 53 percent in September to 55 percent now. That's the same approval rating Franken had in February and is far above his career low of 41 percent in September 2009.

Over the past several weeks, McFadden has repeatedly accused Franken of avoiding debates — the second of three is scheduled Sunday — and for a lack of action on current crises like the rise of ISIL and the spread of the Ebola virus.

The criticism, however, has had little influence on Franken supporter Brigetta Klemek of Cold Spring, who applauded the senator's work ethic despite not being 100 percent in agreement with his politics.

"Everybody thought they were going to get a clown when he came into office, and I like comedy as much as the next person, but he's really kept his shoulder to the grindstone," said Klemek, a 44-year-old home-school teacher. "Tell Al I'd like to see a little more humor from him, but I tell you, he's nobody's fool."

Rolf Iverson, a 68-year-old retired engineer and business owner from St. Paul, was familiar with McFadden's business background, which he sees as an asset compared to Franken's background as a satirist.

"I think [McFadden is] a straight shooter, forthright, and I just feel that's what we need," said Iverson, who is a conservative-leaning independent. "I don't feel that with two senators of the same party that we're necessarily getting the representation that is coherent with what all Minnesotans desire. Not everybody in Minnesota is a Democrat."

Supporters steadfast

While 56 percent of Republicans rated McFadden favorably, more than 75 percent said they would be voting for him, according to the poll. Franken enjoys almost complete support among Democrats, with 93 percent favoring him and even more approving of his job performance — 99 percent.

Franken and McFadden supporters were both steadfast in their choice — 91 percent of Franken supporters saying they'll back him on Election Day and 92 percent of McFadden voters saying the same.

Franken enjoyed the most support among senior citizens, with 57 percent of those ages 65 and up backing him. He runs ahead of McFadden in all age groups except for ages 35-49, where McFadden enjoyed 50 percent of support compared to Franken's 35 percent. Men narrowly support McFadden, while women back Franken 54 percent over McFadden's 33 percent.

Betty Cordes, a 78-year-old cafe owner from Ottertail, said she is among the state's women who will vote for McFadden, based on her frustration with Franken and Washington in general.

"So many of our politicians go into office and forget what they're there for," she said. "There's a difference between a politician and a statesman, and Al Franken is not a statesman, he's a politician. I feel like so much of our government doesn't do what they say they'll do when they get into office. They kind of forget about what's important."

Mike Weder, a 49-year-old father of two from Greenfield, said he generally votes for "whoever tickles my fancy," regardless of ideology or party line. Weder said he's doesn't always agree with Franken, but believes the senator votes with the best intentions for Minnesota and the country.

Weder said he found off-putting McFadden ads in which he pledges not to run for re-election if he voted with his own party 97 percent of the time.

"I don't believe him, and it doesn't make sense either, because we don't know all the details of what's going to happen," Weder said.

Abby Simons • 651-925-5043