By Rachel E. Stassen-Berger and Corey Mitchell

With an early morning video message to supporters, embattled Republican U.S. Rep. Michele Bachmann announced she would not run for re-election next year.

"My dear friends, after a great deal of thought and deliberation, I have decided next year that I will not seek a fifth congressional term to represent the wonderful people of the Sixth District of Minnesota," Bachmann said in the Wednesday morning video. "I've never considered holding public office to be an occupation."

The high-profile congresswoman had a narrow re-election last year and is under federal investigation for her 2012 presidential campaign. A recent poll found that a rematch with her 2012 Democratic challenger, Jim Graves, was a dead heat.

In a polished video message, which included her personal list of what she believes she accomplished during her eight years in Washington, she said supporters could "rest assured" that neither of those challenges influenced her decisions

Graves said that Bachmann's decision shows she "recognized that it would be an uphill battle for her going forward." People in the district, said the millionaire hotelier, are "eager to be represented by a common-sense business person."

Although Bachmann's district is the most Republican in the state, she only bested Graves by about 1 percentage point, or about 4,200 votes, in 2012. In November, Republican presidential candidate Mitt Romney won 56.5 of the vote in the district.

"My decision was not in any way influenced by any concerns about my being re-elected to Congress," Bachmann said in her video message. "If I ran I would again defeat the individual who I defeated last year."

When she ran last year, she battled a perception that her 2012 presidential ran meant that she took her eyes off the needs of the district. In that race, she won the Ames Iowa straw poll in 2011, which felled Gov. Tim Pawlenty's candidacy, and then dropped out six months later when she came in a disappointing sixth place.

The campaign left with more than a $1 million in debt, much of which she has since repaid through the congressional campaign she restarted in February of last year. All told, she spent nearly $15 million on last year's 2012 congressional bid, making that race one of the most expensive in the country.

The presidential campaign also left Bachmann in the ongoing glare of Iowa and federal investigators and in the middle of a civil lawsuit.

The FBI has contacted two former staffers of  her presidential campaign, adding to the swirl of federal and state investigations looking into alleged financial improprieties by top officials in the campaign. The Federal Election Commission and the Office of Congressional Ethics are also looking into her campaign's activities and the Iowa Senate Ethics Committee has investigated payments to her 2012 Iowa campaign chairman, state Sen. Kent Sorenson.

On Wednesday, Bachmann, who ran paid television ads two weeks ago, shocked the political world with her announcement. Even Republicans insiders in the district were surprised to wake up and find the news.

Bachmann herself was out of the country as the Sixth District absorbed her bombshell. She was on a congressional trip to Russia on Wednesday, leaving her eight-minute video statement to speak for her. 

"Looking forward, after the completion of my term, my future is full, it is limitless and my passions for America will remain," Bachmann said. She said she would consider any future path, "if it can help save and protect our great nation for future generations."

Bachmann's announcement instantly set off a political scramble in the Republican-leaning Sixth Congressional District. Many Republican office-holders and former office-holders had interest in the suburban and rural district last year, after Bachmann's failed presidential campaign before she decided to run for re-election, and may look to run in 2014.

See a photo gallery of Bachmann's years in Congress here.