Could Michele Bachmann be in trouble?

An internal tracking poll for Democrats in Minnesota's new Sixth Congressional District shows that the Republican incumbent, back in the hunt for a fourth term, might be vulnerable. Despite a major mismatch in funding and resources, DFL challenger Jim Graves has pulled to within the margin of sampling error -- 46 to 48 percent -- up from 43-48 in June.

This was unexpected. But so was Bachmann's foray into personal accusations of Muslim Brotherhood influence in the top echelons of the U.S. government, an episode that drew widespread condemnation in Congress from Republicans as well as Democrats.

Graves' campaign manager, Adam Graves, noted that this was the first poll he knows of since the national furor over Bachmann's accusations, which he believes alienated independents and centrists. "The people in the middle are going to decide this election," he said.

True, it's a poll funded by Democrats. But reputable outfits such as D.C.-based Greenberg Quinlan Rosner, who did the numbers, aren't usually willing to put their credibility on the line for a fleeting client.

Camp Bachmann was unimpressed.

"Of course, Jim Graves can spend as much money as he wants to get the poll numbers he wants," said campaign spokesman Chase Kroll. "The one thing that he can't buy is the support of the people of the Sixth District."

If Bachmann's people have taken their own polls, Kroll declined to say what the results were. But Bachmann, a longtime Tea Party favorite, has been campaigning hard in her new territory, which is more Republican than her old district. She was in Carver on Sunday for the Steamboat Days parade and then spent Thursday in Waconia, meeting with people in coffee shops and chatting up local politicians and business owners.

Unlike her previous three runs for Congress, Bachmann faces a single opponent, not two, forcing independents and undecided voters to make a choice.

According to Greenberg's analysis, Bachmann has lost significant support from crucial independent voters in the district, with a significant swing in favor of Graves among this key group since June. Wrote the pollsters: "Independent voters account for the bulk of the movement in the race, with a 20-point net shift toward Graves, from a 41-45 percent disadvantage in June to a 52-37 percent lead now."

But Bachmann still has plenty of time to press her cash advantage. At last count, at the end of July, Bachmann had more than $2.2 million in the bank. Graves, a novice politician and wealthy hotelier, had $351,623.

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.