By the time U.S. Rep. Michele Bachmann won her narrow election victory Wednesday morning, the party was over, the crowds were gone, and the staff at the Hilton Minneapolis-Bloomington had already cleaned up.

There were no speeches, no press conferences, no public celebrations of any kind. An aide said Bachmann wanted to keep it low-key.

Instead, her wafer-thin victory over DFL challenger Jim Graves in Minnesota's most Republican district was marked by a tweet and a late morning press release informing supporters that Graves had "graciously conceded."

With all precincts finally reporting, Bachmann had won 50.47 percent of the vote to Graves' 49.26 percent. It was a surprisingly minuscule margin which, together with GOP reverses in state legislative races and ballot questions, is likely to put Bachmann in the center of a debate about the direction of the Republican Party, whose leaders in Congress have not always embraced her.

"The victory wasn't easy," Bachmann told her supporters, "but the things that are worth it rarely are."

Graves, who had mentioned a possible recount during the predawn hours, called Bachmann to wish her well at about 10 a.m.

"We knew it was an uphill battle," he said in an interview after the call. "It is a very conservative district."

His campaign staff waited until all the precincts were in before determining that the vote difference of 4,298 was too large to seek a recount. Bachmann's winning margin of 1.21 percentage points put the race out of the range for an automatic recount under state law.

"We're happy that we avoided a recount -- that's a nightmare situation," said Adam Graves, the candidate's son and campaign manager. "We fought as hard as we could."

Amid a national debate about whether Republican presidential nominee Mitt Romney veered too far to the right on immigration and social issues in his quest to unseat President Obama, Bachmann's unexpectedly narrow victory in a safe Republican district is likely to be noticed.

Even as Romney lost in Minnesota, he carried Bachmann's northwest suburban district by 15 percentage points, beating Obama there 56 to 41 percent. Bachmann also was outpolled by GOP presidential candidate John McCain in 2008, though not by nearly as wide a margin.

Moreover, the district she represented in the last presidential election was not as solidly Republican as the district she was handed as a result of redistricting from the 2010 census.

Fending off attacks by Graves that she has been a divisive partisan, Bachmann took pains in her campaign to portray herself as an "independent voice" who could work with Democrats to get things done back home. The main item in her brief was her role in helping secure approval for the St. Croix River bridge near Stillwater.

But Bachmann gave no indication Wednesday that she is about to back off the aggressively conservative stands that have made her both a lightning rod of criticism from Democrats and a hero to religious and Tea Party conservatives.

Embarking on her fourth term in the U.S. House, Bachmann vowed to "work every day to create jobs for the people in my district and for the people in our nation, while doing everything I can to be an unwavering voice in Washington for our constitutional conservative values."

She also is likely to remain a prodigious fundraiser, as she showed in raising a record $23 million for her re-election bid, much of it using a nationwide e-mail list she developed during her short-lived bid for the presidency last year.

Even Graves, a successful businessman and experienced DFL fundraiser, could not keep up, a sure warning sign to Bachmann's next opponent, if she runs again.

Graves, who raised some $2 million to take on Bachmann, said he thinks her last-minute spending on a barrage of TV ads might have been decisive: "We had very little resources to counteract that."

Staff writers Kelly Smith and Jenna Ross contributed to this report. Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.