ST. PAUL, Minn. -- For Michele Bachmann, the laugh line doubled as a clear message that she thinks she's ready for the rough-and-tumble of presidential politics.
"I had three brothers, no sisters – the best preparation for politics any girl could ever have," the tea party favorite and three-term Minnesota congresswoman told a crowd in Waterloo, Iowa, on the eve of her campaign kickoff.
So far, however, Bachmann's current opponents – all men – are treading lightly, seemingly sensitive both to offending her tea party supporters and to gender concerns.
She's risen in polls in the lead-off caucus state of Iowa and elsewhere since entering the race last month. Surveys show her challenging the front-runner, former Massachusetts Gov. Mitt Romney, in Iowa, and well ahead of former Minnesota Gov. Tim Pawlenty.
It's clear that she's becoming a threat and that her rivals aren't sure how to derail her without risking a backlash.
Take Pawlenty, who's suddenly in her shadow.
When one of Pawlenty's advisers mentioned Bachmann's "sex appeal" as a political asset, his campaign rushed out an apology and the candidate distanced himself from a remark that some interpreted as sexist.
"It's not an appropriate criteria for evaluating a candidate," Pawlenty said.
Last week, he told The Associated Press while campaigning in Iowa that he had no immediate plans to criticize Bachmann as he has Romney.
"I've campaigned for her. I like her. I respect her," Pawlenty said. "I think she and I just bring different things to the table, and I think people will figure that out on their own."
But just days later in a nationally televised interview, Pawlenty called Bachmann's record of accomplishment in Congress "nonexistent."
She responded by describing herself as a fighter who operates "with resolve, and without apology." She also noted Pawlenty's flirtation with policies to tighten industrial emissions and other issues that rile conservatives.
Romney has refused to take the bait when pressed on whether Bachmann is too polarizing to beat President Barack Obama and he didn't hit back when Bachmann criticized his refusal to sign an interest group's anti-abortion pledge.
He's made flattering remarks about Bachmann, a clear attempt not to antagonize her tea party-backers.
Bachmann's standing among them is arguably stronger than any other 2012 candidate because she has loudly championed the grass-roots coalition's smaller-governor agenda.
Hal Nichols, state coordinator of the South Carolina Tea Party Patriots, has a warning for Bachmann's opponents: Tea partyers' votes are up for grabs but the coalition won't look kindly on efforts to disparage Bachmann.
"When others begin to go after her, they're going to be taking on the tea party," Nichols said. "The tea party is going to defend her."
Bachmann is the lone woman field, at least for now. Former Alaska Gov. Sarah Palin, the party's vice presidential nominee in 2008, says she'll announce her intentions in late August or early September. Palin says she's thinking of offering herself up "in the name of service" and is confident she has "common sense, fiscally conservative, pro-private sector policy experience and ideas that can be put to good work for this country."
During Hillary Rodham Clinton's 2000 New York race for the U.S. Senate, Republican opponent Rick Lazio faced backlash from women for his forceful posture in their opening debate, especially when he left his podium to wave a campaign finance pledge at her. In 2008, tone was a consideration for Democrat Joe Biden ahead of his vice presidential debate with Palin.
"There was a lot of talk about how he would handle engaging her substantively but doing so in a way that didn't appear inappropriate or overly aggressive," said Karen Finney, a former Democratic National Committee communications director.
Republicans such as Iowa GOP official Trudy Caviness will watch for the gender dynamics in the race.
"It is new for a Republican woman to run for president," said Caviness, chairwoman of the Wapello County Republican Party in southern Iowa. People are "looking at the new rules of the game and manners of the game."
Not everyone agrees.
For Heidi Smith, a Republican national committeewoman from Nevada, Bachmann "is strong enough to stand up on her own."
"We're past the time of being polite to the lady," Smith added.
Associated Press writer Thomas Beaumont in Ames, Iowa, contributed to this report.