WASHINGTON - Rep. Michele Bachmann holds no leadership position in the House Republican hierarchy, but on Wednesday she debuted in her new role as founder of the 35-member Tea Party Caucus, which has put some of her GOP colleagues on the spot.

Flanked by several GOP Congress members and a multi-racial array of Tea Party activists, Bachmann concluded the group's first meeting with a Capitol Hill news conference intended to allay concerns that congressional Republicans might co-opt the national Tea Party movement. "We members of Congress are not the mouthpiece," she said. "Those involved in the movement are the mouthpiece."

But the rollout of the House Tea Party Caucus also comes amid signs of unease among top GOP leaders and other Minnesota House Republicans, who have largely declined to sign on. Infighting and dust-ups over Tea Party figures who have been accused of racism have caused misgivings about the movement.

Many GOP House members, though happy to join Bachmann in her national "House Call" rally on the Capitol steps last fall, seem leery of playing any formal role in a loosely connected network with groups whose members sometimes play to the fringes of national politics.

It 'will lose its identity'

Another lingering question is whether the movement even wants a formal presence in Washington. Though some Tea Party leaders have been well-connected Republican operatives, the movement prides itself on its grassroots bona fides, which might not be helped by a formal Tea Party Caucus among House Republicans.

"Formality is counterproductive," tweeted Utah Republican Jason Chaffetz, a Tea Party enthusiast who opposes the caucus. "If one person tries to co-opt it, the Tea Party will lose its identity and effectiveness."

While the Tea Party Caucus remains largely symbolic for now, it could position Bachmann for a more prominent national role if the Republicans take back control of the House after midterm elections this fall.

Either way, analysts say the caucus represents the maturing of a national movement. "No populist movement can remain relevant for the long term without coming to grips with the reality of power," said American Enterprise Institute scholar Henry Olsen, author of a recent study on American populism.

But establishment politicians facing a volatile election year remain wary. House Republican Leader John Boehner of Ohio took a pass, citing a personal policy against taking part in any of the many caucuses that form in Congress. Also declining is Republican Whip Eric Cantor of Virginia, who said the Tea Party is "better left with the people."

Kline and Paulsen pass

Among House GOP leadership figures, the only ones to join so far are Indiana Republican Mike Pence, chairman of the Republican Conference, and Rep. Pete Sessions of Texas, chairman of the National Republican Congressional Committee (NRCC), the House GOP's campaign arm.

Troy Young, spokesman for Rep. John Kline, a member of the conservative Republican Study Committee, said that while the Minnesotan "shares their frustrations," for now he is "further reviewing Congresswoman Bachmann's caucus efforts."

Rep. Erik Paulsen, R-Minn., also declined to join, though he has met with local Tea Party members, said his spokesman Mark Giga. "Like any constituent group [Paulsen] is always happy to meet with them," Giga said.

Democrats, often the target of Tea Party anger, appeared to welcome Bachmann's caucus, hoping it might drive a wedge between Republicans and independent voters who might be turned off by Tea Party politics. Bachmann's DFL challenger, state Sen. Tarryl Clark, seized on the meeting to launch a fundraising appeal saying the Sixth District Republican is "cementing her status as the spokesperson for a movement aimed at dividing America."

In her news conference, Bachmann took special pains to assemble a diverse group of supporters to counter allegations of racism that have divided some factions within the movement. First in line to speak was Danielle Hollars, a black Army veteran and "stay-at-home mother of five" from Woodbridge, Va., carrying a 9-month-old baby. "We are not terrorists, we are not racists, we are Americans who care about our country," Hollars said.

Bachmann said the caucus will be a "receptacle" for an anti-tax, small-government movement representing "mainstream American people who have decided to get up off the couch because they want to take their country back."

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