Funnyman-turned-senator Al Franken is running a dead serious campaign for re-election, as some observers see him potentially vulnerable due to President Obama's low approval ratings in Minnesota and a vigorous GOP opponent with eyes on a sleeper upset.

Just how vulnerable is up for debate, and the race nevertheless is seen as favoring the Democrats.

But both sides now acknowledge that, with less than two months to go until Election Day, Minnesota's Senate contest between Franken and Mike McFadden, a longtime Minnesota businessman, is shaping up as a battle.

"We've always known this was going to be a tough race and it's clear we've got one," Franken spokesman Ryan Furlong told FoxNews.com, adding that the campaign is building "a strong and aggressive grassroots organization across the state."

McFadden's spokesman claimed the race has changed "dramatically."

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"We see that [Franken] is clearly afraid. This race is much closer than people realize," spokesman Tom Erickson said.

Franken still leads by a comfortable -- though not too comfortable -- margin in most recent polls.

A survey of registered and likely voters by KSTP/Survey USA in mid-August had Franken ahead of McFadden by nine points, 51 percent to 42 percent. An earlier Rasmussen poll had him ahead by eight points among likely voters, 50 percent to 42 percent.

Terry Madonna, director of the Franklin & Marshall College Poll, said recent polling of the race indicates that "McFadden has a long way to go." The weak spot he will try to exploit, of course, is Franken's ties to the country's top Democrat.

"The biggest thing [Franken] has to overcome is his lineage to Obama," Madonna told FoxNews.com.

Republicans have certainly seized upon Obama's flagging popularity -- down to a 36 percent approval rating in April (this, from a state that voted for him 53 percent to 43 percent over Republican Mitt Romney in 2012). In that KSTP/Survey USA poll, 54 percent of Minnesotans disapproved of the president, and 10 percent weren't sure how they felt. That was down from a 55 percent approval rating in September 2009.

"Obama's approval rating continues to sag," pointed out Larry Jacobs, director of the Center for the Study of Politics and Governance at the University of Minnesota. "That certainly doesn't help Franken. There's a genuine concern from Democrats who are candid about turnout. I think those things could help McFadden."

Analysts thought Franken was responding directly to these red flags when he wrote a letter to the Department of Justice last week, saying he "was troubled by the President's recent suggestion that the Administration has not yet developed a comprehensive strategy to address the growing threat of ISIL's activities in Syria." He went on to say that "Minnesotans of all backgrounds and faiths are committed to seeing this evil eradicated and justice being done."

"Franken is clearly running from his record and distancing himself from President Obama and he looks like he is doing it because he is feeling vulnerable," charged Keith Downey, chairman of the Republican Party of Minnesota.

Republicans say Franken has been a rubber stamp for the White House on important issues of the day, like ObamaCare, foreign policy, Benghazi and the IRS scandal. They have repeated that he's "voted with the president 97 percent of the time," and has been "hiding" from the press and voters until the election draws closer.

But for any of this to stick, two things would have to happen, say experts who spoke with FoxNews.com: Minnesotans have to view Franken's record as interchangeable with Obama's, and Franken's opponent would have to offer a clear and better alternative for the state.

"I think a well-run campaign can give Franken a run for his money, but it hasn't happened yet," said Jacobs, who added that while it's still possible, he has "not seen any evidence" of real vulnerability for Franken so far.

Franken campaign staff told FoxNews.com that the charges they are hiding are baseless, as they are in talks for no fewer than three more debates between the two men before the end of the campaign. Franken, they say, has been running a strong campaign - and on his own record.

As for concerns about the Islamic State, the campaign said the senator's "focus is on making sure that the United States is protected from terrorist threats."

If anything, Franken has been able to exploit a number of missteps by McFadden, who critics say may not be ready for prime time.

Franken's campaign recently seized on an Associated Press report that found that McFadden's investment company made $11 million in a merger in which it moved an American company overseas for tax purposes.

This followed on the heels of statements McFadden made in August about building the Keystone XL pipeline with lower-cost Chinese steel (Northeast Minnesota is considered the Iron Range for its iron ore mining industry).

McFadden has said he was not personally involved in negotiations and didn't know of a possible tax inversion until the merger was announced. As for the steel comment, he told the Mesabi Daily News at the time that Democrats were "trying to reframe the issue. The primary issue is I want the Keystone pipeline built."

For his part, Franken has been a low-profile senator who put his effort into his legislative work rather than raising his profile over the last six years. Where some might have expected the former "Saturday Night Live" star to sling wisecracks to make a name for himself on Capitol Hill, they were wrong. The same goes for his reputation as an acerbic author and liberal talk radio host -- there is little trace of that, even in his campaign ads.

"Al Franken has been a workhorse," said Ken Martin, chairman of the Minnesota Democratic-Farmer-Labor Party (DFL). "I think from the very beginning, from his time on the campaign trail in 2008, Al Franken has shown Minnesotans that despite his show business career, he was a serious candidate, focused on issues in a very serious way."

Martin said his work for mental health and the middle class are high points of his tenure and Minnesotans get that.

But McFadden supporters say the GOP candidate shouldn't be underestimated. He finished an 87 county tour before hitting the State Fair late last month, the launching pad of election season. "Mike is doing a great job connecting with the people of Minnesota, in contrast to Al Franken," Downey said.

But in the end, is it all about Obama? Brook Hougesen, spokeswoman for the National Republican Senatorial Committee, makes the case.

"Al Franken's agenda is Barack Obama's agenda and his blind allegiance to the president will doom him come November," Hougesen said.