WASHINGTON — In a sign of the rapidly shifting dynamics of the Republican presidential contest, Mitt Romney on Monday became the first candidate to run a TV attack ad, slamming Mike Huckabee on immigration in a bid to brake his rival's sharp rise in the polls.
Romney's assault comes amid new polls suggesting that white evangelicals -- a major Republican voting bloc -- have started rallying strongly behind Huckabee after months of wavering among candidates across the field.
Huckabee's surge is especially threatening to Romney, a former Massachusetts governor who has long hoped his rightward tilt would appeal to evangelicals despite their often skeptical view of his Mormon faith.
Romney's new ad, which began airing in Iowa, describes him and Huckabee, a former Arkansas governor and Southern Baptist preacher, as "two good family men."
"Both pro-life, both support a constitutional amendment protecting traditional marriage," an announcer says.
"The difference? Mitt Romney stood up and vetoed in-state tuition for illegal aliens, opposed driver's licenses for illegals. Mike Huckabee? Supported in-state tuition benefits for illegal immigrants. Huckabee even supported taxpayer-funded scholarships for illegal aliens."
Responding to a similar Romney attack last week in a Florida debate, Huckabee defended his Arkansas policies on college aid for students whose parents were illegal immigrants. "In all due respect, we're a better country than to punish children for what their parents did," Huckabee said.
Huckabee has also tried to bolster his conservative credentials on immigration with a new ad of his own, along with a new plan to toughen border enforcement. "Our government has failed us," Huckabee says in the ad. "Build a border fence. Secure the border, and do it now."
Romney spokesman Eric Fehrnstrom called the ad a fair comparison of the candidates' records:
"I think what happens whenever a candidate moves up in the polls is that they attract more attention to their record, and what people will find with Mike Huckabee is someone who is soft on illegals and hard on the American taxpayer."
Huckabee presided over both tax cuts and increases as governor. An offshoot of the Club for Growth, an anti-tax group, has been running television ads criticizing him for raising taxes.
Even with attacks on Huckabee mounting, two polls released Monday found that he had rocketed into the top tier of Republican candidates -- not only in Iowa, which holds the nation's first nominating contest on Jan. 3, but nationwide.
A CNN survey found former New York Mayor Rudolph W. Giuliani supported by 24% of Republican voters nationally, followed by Huckabee at 22% -- a statistical tie. A CBS News/New York Times poll found Giuliani favored by 22% and Huckabee 21% -- also a virtual tie. Both surveys found Romney in third place with 16%.
More ominously for Romney, who has spent millions on television advertising in Iowa, New Hampshire and other early-voting states, the CBS/New York Times poll found Huckabee strongly favored by white evangelicals. Election analysts viewed Romney's decision to risk a backlash from negative advertising as a sign of his heightened concern.
"When you go to the attack ad, that shows you're getting nervous," said Dennis Goldford, a political science professor at Drake University in Iowa.
Huckabee's ability to counterattack is limited by his campaign treasury. The most recent public finance statements show that Romney had raised nearly $63 million by the end of September, including $17.3 million from his own personal fortune. Huckabee had raised $2.3 million at the time, although aides say his fundraising pace has improved in recent weeks.
Bob Wickers, Huckabee's chief media consultant, called Romney's move a mistake, saying it would turn off Iowa voters.
"They want to hear the presidential candidates talk about what they're going to do and why they're qualified to be president of the United States, not why other people should be disqualified," Wickers said. "Mitt Romney hasn't been able to do that. He hasn't been able to connect."
The Republican presidential candidates will debate Wednesday in Johnston, Iowa. The forum will be broadcast at 11 a.m. Pacific time on CNN and Fox News. On Thursday, the Democratic candidates will debate in Johnston. The event will be broadcast at 11 a.m. by the same networks.