WATERLOO, Iowa — Jeanne Tocco is the kind of voter who may decide which Republican will win the Iowa precinct caucuses next winter and emerge as a major contender for the 2012 GOP presidential nomination.

Tocco is one of the legions of conservatives who do not like and will not vote for the nominal national front-runner for the nomination, former Massachusetts Gov. Mitt Romney.

Instead, the homemaker from Shell Rock, Iowa, is searching for a conservative champion who will win Iowa, become the main challenger to Romney, and emerge as the voice of the party taking on President Barack Obama. Her views are fairly typical of Iowa conservatives this summer.

She likes Rep. Michele Bachmann, R-Minn., who formally launched her campaign in Iowa last week and is soaring in the state. She's intrigued by Gov. Rick Perry of Texas, who's still considering jumping into the race. And the only thing she knows about Gov. Tim Pawlenty of Minnesota, who's languishing in the state despite aggressive campaigning, is that he's not very charismatic.

Seven months before Iowa starts the voting, it's turning into a battleground among the populist wing of the party for the right to take on the establishment wing in later states.

The populist wing, which dominates Iowa Republicans, consists of social conservatives and tea party activists. They are motivated by a blend of social issues such as opposition to abortion and gay marriage and fervent opposition to big government as practiced by either party, but especially by Obama.

Its candidates include Bachmann, businessman Herman Cain, and former Sen. Rick Santorum of Pennsylvania. It also would include former Gov. Sarah Palin of Alaska if she jumped in.

The establishment wing emphasizes more traditional Republican issues such as taxes, spending and government regulation. Its candidates include Romney, former Gov. Jon Huntsman of Utah and former House Speaker Newt Gingrich. All are making token efforts in Iowa, all but conceding it.

Perry plausibly could appeal to both wings. Pawlenty is trying to do that, but his effort is raising questions about his authenticity. He built a record on establishment issues but has been emphasizing strong Christian conservative rhetoric this year, which is new for him.

Rep. Ron Paul, R-Texas, is a libertarian who fits comfortably in neither camp.

"In Iowa, it's not between the populist wing and the establishment wing. It's a fight within the populist wing," said Dennis Goldford, a political scientist at Drake University in Des Moines.

Right now, Bachmann is leading that fight.

A Des Moines Register poll last week showed her neck and neck with Romney in the state, with all other rivals far behind. She kicked off her campaign in Waterloo, where she was born, and returned for a three-day bus tour around the state over the holiday weekend.

"She's more like me than any other candidate," said Carole Deeds, a realtor from Cedar Falls.

Jim Strubel of Waterloo also likes Bachmann, but he's open to other candidates, most notably Texas' Perry. "I hope he gets in," Strubel said. "He's an excellent speaker. He's dynamic."

The rest of the populist wing is well behind.

Cain, a former CEO of the Godfather's Pizza chain, is winning some support with a vow to treat government like a business. Santorum, who campaigned in Iowa last week, has not managed to break through.

Palin, who visited Pella, Iowa, last week to attend the premiere of a documentary movie about her, continues to draw fans. But her long tease about running left the door open to Bachmann to seize the tea party mantle, and left some Iowa conservatives wondering if Palin's time has passed.

"I like her, but she's pretty busy with other things," said Patricia Smith of Waterloo.

Pawlenty is struggling to catch on. Despite TV ads, he's left little impression on Republicans interviewed around the state.

"I really don't know too much about him," said Jeanne Tocco. "Not too charismatic."

MORE FROM MCCLATCHY

Tim Pawlenty takes low-key Florida campaign swing

Palin visits Iowa, but still won't say if she's running

Michele Bachmann announces 2012 presidential run in Iowa

For more McClatchy politics coverage visit Planet Washington