DES MOINES, Iowa — Republican candidates are taking Iowa by storm as the clock ticks down toward the first US presidential vote, hoping to propel their campaigns with support from the small state's Christian conservatives.

Candidates have increased campaign appearances in the all-important state whose caucuses will officially launch the 2012 primary season January 3 with some 150,000 voters expected to give an early vote on who they want as Republican nominee to take on President Barack Obama, a Democrat.

Some, like Representative Michele Bachmann and former senator Rick Santorum, have tirelessly crisscrossed Iowa and its endless cornfields, playing up their support for its central agricultural, biotechnology and green energy industries in a bid to fight their flagging poll numbers.

For those trailing behind, the race is an especially frantic effort to keep their campaigns alive and avoid running out of cash so they can put up a good fight in other early states like New Hampshire, South Carolina and Florida.

While former pizza boss Herman Cain is in the lead in Iowa, with 20 percent support according to a RealClearPolitics average of polls, all eyes are on ex-Massachusetts governor Mitt Romney, the Republican frontrunner hoping to quash his rivals early but battling worries about a repeat of his 2008 defeat.

Romney poured campaign funds and spent endless hours of campaigning four years ago only to lose to evangelical Christian favorite Mike Huckabee, an ordained minister, and eventually the nomination to Senator John McCain.

So this time, he has chosen to take a more low-key approach, making far fewer public campaign appearances.

An Iowa win could further his chances of scoring a one-two punch with a subsequent victory in the New Hampshire primaries on January 10, for which he is already tipped to secure a significant advantage, and pave the way to score the nomination that eluded him last time around.

A caucus victory -- or even a second- or third-place showing -- would give any candidate a big shot in the arm and a central place in the media spotlight, possibly propelling the campaign for other key early state wins to become the Republican Party's nominee to fight Obama in the November 2012 elections.

"Iowa is ground zero, where else would you be?" Bachmann asked supporters Wednesday in Des Moines.

But Iowa voters, who cherish their first-in-the-nation role, are notoriously demanding and often remain undecided until the last minute after much face time with the different candidates.

"The campaign is volatile," said Steve Roberts, a retired Republican lawyer who has closely followed presidential campaigns since Gerald Ford in 1976. "I haven't made up my mind on what candidate I'm going to support."

And the only way to get to an Iowan voter's heart is to demonstrate commitment and enthusiasm with up close and personal outreach, according to Timothy Hagle of The University of Iowa.

"All the candidates need to engage in the grassroots, retail politics that Iowans expect," he said.

"Again, it's a bit of a cliche, but Iowans like candidates to shake your hand, look you in the eye and tell you where they stand."

Undeterred by an average of just four percent support in Iowa, Santorum is a firm believer that his determination will see him make a break.

And early this month, he proudly boasted being the first candidate of this campaign season to have visited all of the state's 99 counties.

The battle is fierce, with even the smallest of towns being lavished with attention from candidates traveling by car, bus or plane to visit factories, cafes, pizzerias and even individual homes in search of elusive personal connections with voters.

"It's not rich people that are sending money to my campaign, it's real people," Bachmann said during a dizzying Iowa swing to climb back from seven percent average support in the state to regain her strong summer showing.

"I've been fighting in the lion's den in Washington, DC for the last five years against the out-of-control spending."

In this largely white state, Republicans are especially elbowing each other for the support of conservative evangelical Christians.

Huckabee, the 2008 winner, did not go on to win the nomination, but gained a huge boost in national prominence and is a now a popular best-selling author and speaker who hosts his own talk show on Fox News.

And the Democratic winner was none other than Obama, who emerged victorious from a bruising battle with party rival Hillary Clinton, now his top diplomat.