VINTON, Iowa — Global warming is not a political issue for Mike Huckabee. It's a religious one.

An ordained Southern Baptist minister, Huckabee doesn't recoil at capping greenhouse emissions. He says that's because he lives in God's house.

"I believe that God is the creator of the Earth. He owns it. I'm his guest. It's not mine. I have a responsibility to take good care of it," he tells about 80 people packed into a room at the Kirkwood Learning Center in Vinton, located between Cedar Rapids and Waterloo in eastern Iowa.

Huckabee is shaking up the Republican presidential race in Iowa. His underfunded campaign has climbed in public opinion polls to challenge frontrunner Mitt Romney.

His spiritual roots and longtime opposition to abortion and same-sex marriage — he favors constitutional amendments outlawing both — may be fueling the rise, with Huckabee touting himself as the "Christian leader" and "authentic conservative."

Like GOP televangelist and presidential candidate Pat Robertson in 1988, Huckabee erects no barrier between faith and politics. He says unequivocally that his spiritual beliefs drive his political beliefs, including his concern about poverty and his compassion for illegal immigrants.

His deep faith, easygoing manner and self-deprecating humor impressed many of the Republican faithful who braved a chilly November evening to get a glimpse at the budding GOP star.

"I totally like his values, his sense of humor and the way he can communicate with people," said Steve Cory, a Republican from Vinton. "I connect more with Mike's Christian values than Mitt Romney."

A former Christian broadcaster and noted orator, Huckabee has a quick wit and pitch-perfect delivery. He captivates campaign audiences with humor and homespun stories.

"If it was all about the money, then we might as well put the presidency up on eBay," he quipped earlier in Waterloo, Iowa, generating big laughs.

"Huck," as he is known in Arkansas, has a gentle radio voice, like Garrison Keillor's. It's the type of voice that could reach out and provide comfort on a lonely midnight drive across a desolate stretch of prairie.

When he entered the presidential race, Huckabee was given little chance of catching fire. He had little name recognition and trouble raising money. He was best known as the governor who had lost 110 pounds.

Huckabee is running as a conservative populist, saying he cares more about low- and middle-income Americans than wealthy business executives.

"I'm not a Wall Street Republican, I'm a Main Street Republican," he likes to say.

Huckabee is a staunch supporter of the Iraq war. He favors a 30 percent national sales tax that, he says, would replace the federal income tax and shut down the Internal Revenue Service.

To many Christian conservatives in Iowa, Huckabee is the more palatable choice in this year's GOP field, which includes former New York City Mayor Rudy Giuliani, a twice-divorced Catholic, and Romney, the former Massachusetts governor, a Mormon who once supported abortion rights.

"I like the fact that he seems to be fairly consistent in his views. He's not saying one thing in Arkansas and another here," said Debbi McCormick of Shellsburg, Iowa.

Huckabee started his professional life working for televangelist James Robison. He spent 12 years as a pastor, presiding over Baptist churches in Pine Bluff and Texarkana. In both communities, he hosted weekly community shows on local Christian television stations.

Huckabee left the pulpit in 1992 and entered politics. He won a special election as lieutenant governor in 1993, then assumed the governorship in 1996 after incumbent Jim Guy Tucker was convicted of fraud in the Whitewater scandal and resigned. Huckabee was later elected in his own right in 1998 and won re-election in 2002.

He worked to improve schools and roads, touted preventive health care and pushed for health insurance for poor children. He presided over some tax increases, which have earned him scorn from the anti-tax group Club for Growth, which accuses him of being a "liberal tax and spender."

Huckabee supported a sales tax increase to fund education after the Arkansas Supreme Court ruled the state's education funding system was unconstitutional. He supported a gas tax hike to improve roads.

Huckabee, who refers to Club for Growth as "Club for Greed," said as governor he did not have the luxury of balancing the state's budget out of thin air.

He said he also presided over 90 tax reductions, including an income tax cut that reduced the state's coffers by $90 million annually. Most of the other cuts were small, including a sales-and-use-tax exemption for the Salvation Army.

Huckabee's record on illegal immigration has become fodder for GOP rivals Romney and Fred Thompson. As governor, he supported President Bush's plan to create a path to citizenship for illegal immigrants. Huckabee also fought for in-state tuition and taxpayer scholarships for the children of illegal immigrants.

Now, campaigner Huckabee talks tough on immigration, saying he would tighten the borders and impose tougher penalties on employers who knowingly hire illegal immigrants.

But he says he is not angry at the people who cross the nation's borders illegally. If the minimum wage in Canada were $100 an hour, he says, many Americans would be slipping across the northern border.

Other aspects of Huckabee's record in Arkansas have come under scrutiny as he campaigns for president. As governor, he was accused of several ethical lapses, and his judgment was questioned after he supported early release for a rapist who later killed a woman.

He was reprimanded five times in 14 years by the Arkansas Ethics Commission. Some were for minor offenses.

One of the most serious resulted in a $1,000 fine after the commission ruled Huckabee failed to report that he had paid himself $14,000 from his 1992 U.S. Senate campaign and $43,000 from his 1994 lieutenant governor's campaign.

Near the end of his term in 2006, Huckabee and his wife were criticized for accepting gifts from friends to furnish their new home. Friends of the couple established a wedding registry in their name at two Arkansas stores, soliciting housewarming gifts.

The couple, married in 1974, said the registry was listed under weddings because there was no housewarming category.

More potentially damaging was Huckabee's involvement in the release of Wayne DuMond, who raped a distant cousin of Bill Clinton's in 1985. While DuMond was home awaiting trial, two men forced their way into his house and castrated him. DuMond maintained his innocence, and his case was taken up by Huckabee and others.

After he was elected in 1996, Huckabee announced his desire to commute DuMond's sentence and said he had questions about his guilt. He met privately with the State Parole Board. Shortly after that meeting, the board voted to parole DuMond.

A year after he left prison, DuMond murdered a Missouri woman. His DNA was found under her fingernails. Huckabee, who emphasizes that he did not pardon DuMond, says no one could have known that DuMond would attack another woman.

"It was one of those things I just feel horrible about," he said earlier this year. "You just ache all the way to the bone over what happened."