Nov. 12 (Bloomberg) -- When he encountered a protester dressed as a snowman at an event in Iowa, Republican presidential candidate Mike Huckabee welcomed the party-crasher.

Huckabee suggested that the man give the crowd at a campaign event at the Kirkwood Community College Center, in Vinton, his critique of Republican climate-change policies.

The incident illuminates a key facet of Huckabee's long- shot bid for the White House. Though he's a Scripture-quoting champion of social conservatives, his populist economics may limit his ability to broaden his support among Republican constituencies.

Huckabee backs a national sales tax that subsidizes the poor, favors more spending on preventive health care and the environment, says free-trade agreements hurt U.S. workers, and contends Republicans have forsaken Main Street for the interests of Wall Street.

The result is a kind of populist fusion -- he's also anti- abortion, pro-gun and a foe of gay marriage -- that has catapulted Huckabee to the first tier of Republicans in Iowa.

An average of polls compiled by the Web site Pollster.com places Huckabee second, behind former Massachusetts Governor Mitt Romney, in the state's caucuses, and ahead of former New York City Mayor Rudy Giuliani and ex-Tennessee Senator Fred Thompson.

Long Odds

That gives Huckabee, 52, a chance for an Iowa breakthrough. Even if he pulls that off, campaign experts say, post-Iowa he faces a difficult task trying to expand his base from Protestant evangelicals to voters concerned about taxes and spending and those who focus on national security.

John Feehery, a party strategist, said Republicans need a three-cornered stool to build a solid candidacy. For Huckabee, ``one leg is too tall and the others are too short,'' Feehery said.

Citing his humble beginnings in Hope, Arkansas, Huckabee, an ordained Baptist minister, is comfortable railing against moral decline one moment and blasting over-paid executives the next.

``I'm one generation away from dirt floors and outdoor toilets,'' he told Iowans at a recent visit to Doughy Joeys Peetza Joynt, in Waterloo.

Huckabee is facing his heaviest resistance from economic traditionalists who are leery of his populism and Arkansas record.

Unacceptable to Republicans

``He's the only guy in this field who's a big fan of bigger government and higher taxes,'' said Pat Toomey, chief executive officer of the Club for Growth, a Washington-based group that supports limited government. ``It's unacceptable to most Republican voters.''

Toomey brands Huckabee a ``tax hiker.'' Similarly, the Cato Institute, a Washington-based organization that favors small government, gave him an ``F'' on taxes and spending in 2006.

Among the transgressions the groups cite: Huckabee's backing of a 1999 gasoline-tax increase, a cigarette tax boost, a round of 2004 tax increases, a state levy on beer, and a tax on Arkansas nursing homes. He also supported raising the state minimum wage to $6.25 and hour from $5.15.

Huckabee says he ``loves'' taking on the Club for Growth. ``Is it morally responsible for me to know that I'm enjoying a low price because some nine-year-old worked 20 hours last night?'' he asks.

Economic conservatives are wary of Huckabee's critiques of free trade and potshots at Big Business. ``It's really troubling'' the way corporations reward underperforming chief executives with ``unbelievable bonuses,'' Huckabee said in an interview Nov. 7.

Scrambling Iowa

While few political pros see Huckabee as the nominee, he can still leave an imprint on the race by scrambling Iowa's results. If he eclipses the favored Romney, who is competing for the same ``values voters'' as he is, Huckabee may derail the former Massachusetts governor's bid.

Similarly, beating more prominent and better-funded rivals such as Giuliani and Thompson would inflict wounds that could prove damaging to the Republican stars as the campaign winds on.

First, Huckabee needs to find a way to expand his appeal. Aside from his problems with economic conservatives, he faces skepticism from Republicans whose chief concern is national security.

Though he says the U.S. should do ``whatever it takes'' to assure victory in Iraq, Huckabee lacks the national-security credentials of Giuliani and Arizona Senator John McCain, a leader in Congress on military issues.

Sounding like another aspiring politician from Hope, Arkansas -- former President Bill Clinton -- Huckabee said his lack of experience shouldn't be disqualifying.

`Clear Convictions'

``Many of the great leaders who dealt with crises didn't have a foreign-policy resume when they went into office,'' he said. ``But they did have clear convictions of what was right and what was wrong.''

Experts caution that even if he scores big in Iowa's January caucuses, Huckabee still lacks the financial muscle to sustain his momentum. As of Oct. 1, he had $651,301 to spend on the race, compared to Giuliani's $11.6 million, Romney's $9 million, and Thompson's $7.1 million.

``Every month somebody has written my obituary,'' Huckabee said. `We're moving.''

One of Huckabee's assets has been his easygoing style and quick wit. During a Nov. 7 forum at the University of Northern Iowa, a mobile phone interrupted his comments. ``That was probably Dick Cheney wanting to take me hunting,'' cracked Huckabee. ``No way.''

Huckabee's performance in candidate debates is fueling speculation that he could wind up as a vice-presidential pick. Huckabee is doing nothing to discount such talk.

``It's better than telling me to go home,'' he said.

To contact the reporter on this story: Heidi Przybyla in Washington at hprzybyla@bloomberg.net.

Last Updated: November 12, 2007 00:17 EST