Republican voters in Iowa will kick off the 2012 U.S. presidential election campaign Tuesday with caucus voting, the first step in choosing a candidate to run against President Barack Obama next November.  The campaigning in Iowa among six Republican contenders is intense in advance of Tuesday?s vote.

It?s the final push for votes in Iowa and former Pennsylvania senator Rick Santorum is surging in the polls.

At an event for Santorum in a restaurant drew an overflow crowd that braved the cold and hordes of journalists from around the world. ?If you are looking for someone you can trust, someone who's authentic.  Then I?ll put myself out there. I know you aren't going to agree with me on everything.  What you do know is I'll say what I believe and do what I say,? he said.

Don Todd will vote on Tuesday.  He?s leaning toward Santorum. ?Just someone with more basic American values than what the Democratic Party has turned into.  That?s what this Iowan is thinking and a lot of the people that I know,? Todd said.

Marty Miller came all the way from Florida to follow the candidates around Iowa. ?Somebody that can turn this country around and get us back where we belong, where everybody is proud of our country,? Miller said.

Santorum is trying to catch former Massachusetts governor Mitt Romney, who?s leading in the polls.

?Get out and vote, vote, vote!  Get your friends to go to the caucuses!,? Romney said at one campaign stop.

Texas Congressman Ron Paul, running second at the moment, also fired up supporters at a rally in downtown Des Moines. ?The enthusiasm is growing by leaps and bounds and bounds.  The crowds are getting bigger,? Paul said.

Support for former House Speaker Newt Gingrich has been sliding, but he?s still hoping for a last minute surge.

"Look, I think this is a volatile environment, where people are going to walk in, undecided or semi-decided, and maybe as many as 50 percent could switch during the course of the caucus," Gingrich said.

Polls show Gingrich may be right and the Iowa caucus race remains unpredictable.