Mike Huckabee seems equally comfortable chatting it up on The Colbert Report or speaking to an audience of evangelical leaders. His easygoing style and populist message may be why he has catapulted from the also-rans to frontrunner status among Republican presidential candidates.

According to the latest polling, Huckabee, 52, has toppled Mitt Romney from the top in Iowa. At least two polls have him ahead in South Carolina. But he still remains in fourth place -- at best -- in New Hampshire.

More remarkably, while Huckabee started out as a virtual unknown among voters beyond Arkansas, the Rasmussen poll declared him the national frontrunner on Dec. 6. He has since receded a bit, but continues to lead in early voting states like Michigan and Florida.

Huckabee's surge in the GOP race reflects what appears to be a demand for less vitriol, along with conservative grounding, among Republican voters. His personality and endearing Southern charm have been assets in the debates, where he has stood out with his easy, humorous one-liners and compassionate responses on contentious issues like illegal immigration.

"He's probably the best speaker out there," said John Gizzi, political editor for Human Events.

"He is personally engaging and I think people are starting to see that a little more as time goes forward. I think he's found a formula now," said Mark Wrighton, a politics professor at Millikin University in Illinois.

But while Wrighton suggests Huckabee's surge in popularity is the result of socially conservative voters finally getting engaged and enthusiastic for a candidate, the former governor of Arkansas is now facing much closer scrutiny, and a harsh evaluation from both capitalist purists and neoconservatives concerned about national security types.

Anti-tax groups and some of the other Republican candidates have accused Huckabee of raising taxes in Arkansas more than $500 million when he was governor from 1996 to 2007, and supporting college tuition for the children of illegal immigrants -- two things Huckabee has neither denied nor apologized for. His call to eliminate the income tax and replacing it with an across-the-board sales tax, or "fair tax," has spurred as many proponents as critics.

He has also taken heat recently for his role in the parole of rapist Wayne Dumond in 2002. After his release, Dumond raped and murdered a woman in Missouri, and he was a suspect in another rape/murder when he died in jail in 2005.

"The case is the wild card in Mike Huckabee’s record, the single most controversial event during his time in the Arkansas governor’s office. And it is a potential threat to his now-soaring candidacy,” National Review writer Byron York wrote after the news broke.

So far, Huckabee hasn't demonstrated a penchant for getting too entangled in explanations about his actions as governor.  Still, he has been berated by conservative icons who say he is not a "movement conservative."

Recently, Huckabee wondered aloud why he is in talk show host Rush Limbaugh's sights, and used his "aw, shucks" charm to vie for a spot in Limbaugh's good graces.

"I love Rush Limbaugh. I always loved his show. I think he's been great for conservative movement," Huckabee said. "I only hope that Rush can love me as much as I love Rush, because he's been a very clarion voice for the conservative movement. Somebody said something to upset him. I don't know who, I don't know what. I can't fix what I don't know. All I can tell you is he's been one of the great voices, not just conservative, I would say common sense voice," he said.

Huckabee also suffers from concerns about whether he can handle tough foreign policy issues. He raised a stink among some conservatives, and chief rival Romney, when he wrote in Foreign Affairs magazine that the Bush administration has suffered from an "arrogant bunker mentality."

Even the administration felt compelled to respond.

"The idea that somehow this is a go-it-alone policy is just simply ludicrous," Secretary of State Condoleezza Rice said at a news conference Friday, without naming Huckabee. "One would only have to be not observing the facts, let me say that, to say that this is now a go-it-alone foreign policy."

Huckabee also faces questions of whether he can walk the line between president and preacher. An ordained Southern Baptist minister who advocates teaching creationism or "intelligent design" alongside evolution in public schools, he wins appreciative enthusiasm from evangelical Christians, although he has been criticized by some Catholics who say he is trying to steal the Jesus mantle for his political goals. He's also accused Mormons of being cult members, but posed the statement as a question, leaving room for him to back up and reverse course.

On Sunday, the candidate went on CBS' "Face the Nation" to say he is running as president of all America, and not just Christian America.

"That's how I served as governor," he said. "People look at my record and they didn't see that I put a tent out on the capitol grounds and had healing services, and I didn't replace the dome with a steeple. I governed. We improved education. We rebuilt the road system. We brought health care to children who didn't have it. We reformed the welfare system. Those were the things that I focused on as governor.

"When people take a look at that, they're going to see that it was my faith that drove me to care about things like hunger and poverty and the people that didn't have anybody out there advocating for them. Real faith does that for you. It makes you concerned about everybody with a sense of equality," he said.

The governor also responded to criticism of a Christmas ad he ran in which he invoked Jesus' name and appeared before a bookshelf that was lit up in such a way that it resembled a cross.

"Everyone thought that we were so smart and clever. The truth is, it was a bookshelf. We hurriedly put the spot together. It wasn't scripted. I ad-libbed the spot. It was done at the end of a long taping day, and really kind of a thought of, well, let's do a Christmas spot just in case we decide to use it maybe on our Web site, maybe for broadcast, but probably just for the Web site," he said. Soon after his television appearance, he took to the pulpit of a mega-church to address a crowed of 10,000.

Pastor Joel Osteen, who runs Lakewood Church in Houston, says Huckabee has achieved the right balance between preacher and politician. "From what I've seen, I don't think he's overdone it. I think he's just -- you know, he's a Baptist pastor. That's in him. And I think he's just standing up for what he believes in."

Huckabee is a strong supporter of gun rights and the death penalty, and he is a strong opponent of same-sex marriage and abortion. He lost 110 pounds a few years ago and wrote a book about getting healthy. He has stated repeatedly that health is a bigger problem for Americans than health care.

The jury is out as to whether Huckabee can win the general election, but he has definite running-mate potential, say analysts, particularly if he can keep on the charm and away from sticky scandals and bad news.

"I think you have second-tier candidates, in both parties, doing V.P. auditions, and frankly, I think Governor Huckabee is a fine candidate," said Wrighton.