MASON CITY, Iowa - Corn kernels, corn flour, and corn oil filled a line of jars behind Gov. Christie as he patiently listened to the case for ethanol Saturday morning at a production plant, surrounded by harvested cornfields in Jewell, Iowa.

"I think people really aren't grasping what this could mean for America, especially rural America," said Matt Merritt, public relations director for the biofuel company POET, of cellulosic ethanol production - a relatively obscure topic, but not for a presidential candidate in agriculture-rich Iowa.

"A lot of this is about educating folks," said Christie, who has supported a federal renewable fuel mandate that benefits ethanol producers. "And listen, showing some political muscle, too, that never hurts. And signing up caucus-goers and making sure people understand how important this is."

Christie came to Iowa riding a wave of new endorsements in New Hampshire that won him fresh attention last week. His campaign promoted new polling that showed Christie rising to fourth place there and garnering the highest favorability of any GOP candidate in the first-in-the-nation primary state.

Then he returned to Iowa. Recent polls show Christie averaging 2.3 percent among Republican caucus-goers who will cast the first votes in the nomination race Feb. 1 - and who skew more socially conservative than GOP voters in New Hampshire, where Christie has focused his campaign efforts for its Feb. 9 primary.

While Christie hasn't gained momentum in Iowa, some Republicans say he could still mount a successful finish there. Businessman Donald Trump has led in polls, though Texas Sen. Ted Cruz has been seen as gaining strength by coalescing conservative and evangelical voters.

Among the so-called Republican establishment candidates, no front-runner has emerged.

"One of the untold stories of the Iowa caucuses, eight weeks from now, is that a large segment of the Republican establishment vote is still a complete jumble," said Matt Strawn, a former chairman of the Iowa Republican Party. That "presents an opportunity for Gov. Christie in Iowa."

Christie "is probably getting a second look by some, but not a lot" of mainstream Iowa Republicans, said Douglas Gross, a lawyer in Des Moines who was Iowa chairman of Mitt Romney's 2008 presidential campaign.

Even without initial enthusiasm for Christie's campaign, "a lot of times, this thing is a war of attrition," Gross said. If rivals such as former Florida Gov. Jeb Bush and Florida Sen. Marco Rubio can't gain support, Christie could benefit. "If he could finish third, it would be a tremendous win," Gross said.

Outside the ethanol plant Saturday, Christie declined to set expectations for his Iowa campaign. "I just think I have to do well here," he said, after noting that success in New Hampshire isn't dictated by Iowa. "In a 14-person race, that could be a pretty broad finish. So we'll have a much better idea in January how we define well."

To have a chance in Iowa, observers said, Christie has to show up. "If you're not on the radar at all, you can't expect to be noticed," Gross said.

At a series of campaign events Friday and Saturday, Christie tried to sell Iowans on his message as the most experienced candidate - particularly, as a former U.S. attorney, in dealing with terrorism, a topic that occupied almost the entirety of his opening pitches.

"I wanted to talk to you a little bit this morning about energy policy obviously, and I will," Christie said at an annual meeting of rural electric cooperatives Friday morning. "But I think it's much more important at the start to talk about the events that are happening around the world."

Christie then spent 20 minutes talking about national security, drawing a chuckle from the crowd in the West Des Moines Sheraton with an analogy about the presidential race and trucks. "It's exciting when you see something new. When you see that new truck in the showroom," with "all kinds of new bells and whistles on it," Christie said. "Then you get stuck in the mud."

He repeated the comparison - and call for experience - at a town-hall meeting at a brewery in Mason City. "We're up against a group of folks who want to kill us," Christie said. "We cannot afford for this race anymore to be about entertainment or fun."

In an obvious swipe at Trump, he later said: "We do not need reality TV in the Oval Office, everybody."

While Christie talked up his training as U.S. attorney - describing his familiarity with FBI acronyms and "actionable intelligence" - the questions posed by voters went far beyond terrorism, from Planned Parenthood to religious freedom to New Jersey's gun laws.

"My job has been to make sure they don't get worse," Christie said of the gun laws, before touting the New Jersey Assembly's failure on Thursday to override his veto of a gun-control bill. The Senate voted to override Christie in October, but a successful Assembly vote is also needed.

"I haven't had one veto overridden now in almost six years," Christie said. He didn't mention the substance of the bill - which would require notification of law enforcement if a person seeks to expunge a mental-health record in order to buy a gun - or that it had initially passed the Assembly unanimously, with support of the Republicans.

Christie got favorable reviews from Iowa voters, but few interviewed over the course of two days said they were committed to him. "When I listened to Carly [Fiorina], I was going to vote for Carly," said Bob Johnson, 74, of Mason City. But he said he also approved of Christie's experience and ideas.

Though Johnson put Christie among his preferred candidates, he said he was still bothered "big time" by the governor's reception of President Obama after Hurricane Sandy - a bipartisan moment in the run-up to the 2012 presidential election. "There's a reason that he's at 3 percent," Johnson said.

After hearing Christie talk national security at a forum in Fort Dodge, Deb Zemke, 67, of Knierim felt he could "restore confidence of the American people" and "push through his ideas."

But Zemke - who also is considering Cruz, Rubio, Fiorina, and neurosurgeon Ben Carson - wasn't sold on Christie's pitch that executive experience was critical. "The others are just so bright," she said.

However Christie finishes in the caucuses, his placing will matter less than its portrayal in the media, said Dennis Goldford, a political science professor at Drake University.

Even if Christie edges out other establishment-type Republicans, if he finishes with less than double digits, "it's sink or swim in New Hampshire," Goldford said.

But if Christie were to finish substantially better, "the story is, 'Iowa gives Christie an opportunity in New Hampshire,' " Goldford said. Candidates will lower the bar "so they can be seen as exceeding it by leaps and bounds."

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