Charlie Riedel, Associated Press
Republican presidential candidate, Rep. Michele Bachmann, R-Minn., talks to congregants during a campaign stop at Jubilee Family Church in Oskaloosa, Iowa, Sunday, Jan, 1, 2012.

VALLEY JUNCTION, Iowa — Republican Michele Bachmann dwelled Monday on her Iowa roots, the theme of her only late-campaign television ad and a point she hit often on a door-to-door walk through a quaint business district outside Des Moines.

Fighting to fend off a caucus nightmare on Tuesday, Bachmann contrasted herself with all of her opponents and lobbed her hardest shot yet at Rick Santorum. The former Pennsylvania senator has rocketed to contender status while she has been stuck at the back of the GOP field, recent polls show.

Bachmann criticized Santorum for voting for a symbol of wasteful Washington spending, Alaska's "Bridge to Nowhere." She also jabbed him for once endorsing Sen. Arlen Specter, then a fellow Pennsylvania Republican who joined the Democratic Party in 2009. "Arlen Specter supplied the 60th vote that gave us Obamacare and gave us taxpayer-funded abortions. I never would have supported Arlen Specter, who is a pro-abortion candidate," she said.

Bachmann, the winner of a summer test vote in Iowa, is trying to rekindle a campaign spark and keep her White House hopes alive. Low on money, she didn't make it into the pre-caucus ad battle until Monday and even then wasn't airing it on every Iowa TV station.

The ad twice mentions Bachmann's Iowa heritage and calls her "one of our own."

Bachmann was born in Waterloo but later moved with her family to Minnesota, where she was elected to Congress in 2006.

While campaigning Monday, Bachmann stressed her native-state status.

"I believe without a shadow of a doubt that Iowans want to get behind their values and I believe I best represent their values," she said after fighting her way through thick crowds at some businesses.

Bachmann has bet on her support among evangelical Christian voters and said she expects full congregations to caucus on her behalf.

She insists she'll go on no matter what happens Tuesday night. She and her top campaign advisers have tickets to South Carolina — opting to head there rather than New Hampshire, which votes one week from Tuesday, on Jan. 10. The Bachmann team will fly commercial rather than on chartered flights like other campaigns with more money at their disposal.

Supporters who greeted her Monday said they weren't giving up hope for a strong finish.

Larry and Mary Abbott, retirees from Des Moines, said they intended to caucus for Bachmann no matter what the polls reflect.

"I think the polls are wrong. I think the polls are skewered," Larry Abbott said.

The Abbotts said they were getting daily contacts from the campaign and were confident in her chances.

"People are going to be surprised," he said.

"I hope they are," added Mary Abbott.