DES MOINES, Iowa — He seemed to come out of nowhere: A former Baptist preacher and ex-governor who was so little known among Republicans that many of them could not even name the state he once led (Arkansas). But Mike Huckabee turned from asterisk-status to giant-slayer in Iowa on Thursday night.

For former Gov. Mitt Romney of Massachusetts, his loss here will register as a deep blow to his candidacy — a failure bound to worry establishment Republicans and wealthy donors who have viewed him as their man, and also energize and inspire Republicans who are backing Sen. John McCain in the New Hampshire primary on Tuesday.

Romney's drive to the Republican nomination was supposed to begin by looking formidable and confident coming out of Iowa, where he had long been the front-runner. He now heads to New Hampshire clearly wounded and a target for even more rivals, such as former Mayor Rudolph W. Giuliani, former Sen. Fred Thompson, and McCain.

Huckabee, a folksy and fairly plain-speaking politician with a sense of humor that many Iowans enjoyed, appealed to Republican caucus-goers who put a premium on a candidate's Christian faith — and who were deeply wary about seeing a Mormon, Romney, become president. But Huckabee also struck many populist themes that have deep appeal to middle-class Iowans and farmers, promising to tailor his economic priorities to their needs and taking tough stands on a key issue here, immigration.

But Iowa voters are not New Hampshire voters, as Huckabee and his advisers are well aware. Devoutly religious voters do not exist in nearly the same numbers in the Granite State; rather, the fervent anti-tax sentiment among Republicans there is likely to clash with Huckabee's record of raising taxes in Arkansas.

McCain, despite finishing behind the top two candidates in Iowa, now appears to be in a strengthened position in New Hampshire, given Huckabee's weak operation there and Romney's failure here. The Iowa results could also help Giuliani and Thompson, given that Romney had seemed like such a major foe.

Huckabee also lacks teams of political veterans in New Hampshire, South Carolina, and the states with primaries to follow — certainly nothing to match the operations McCain and Romney have spent a year building.

And Huckabee's recent missteps, such as a bungled negative advertising attack and his misstatements about Pakistan and immigration, and his paucity of foreign policy experience will be grist for his rivals.

"Huckabee has a skeletal organization in New Hampshire and he's barely up on the airwaves, and despite winning Iowa he looks anything like a front-runner here right now," said Dante Scala, a political scientist at Saint Anselm College in Manchester, N.H. "The evangelical vote is a much different animal here, probably only one out of seven likely Republican vote — Huckabee really has no base to start with here."

But Iowa bestows an advantage on its winners that has trumped bodies and dollars in other states before: political momentum. Huckabee now has substantial wind at his back; political analysts say his success in Iowa could translate into a 5 or even 10 point boost in the polls in New Hampshire, which votes on Tuesday.

"Huckabee could easily struggle in New Hampshire but still try to re-ignite himself in South Carolina, where he has a base," said Steffen Schmidt, a professor of political science at Iowa State University. "His bigger problem is that he doesn't have a national campaign or money for the big expensive primaries that are coming."

Romney, like a past candidate from Massachusetts, John Kerry in 2004, had hoped that a victory among strangers here would add luster to his candidacy among people who know him better as a resident of a neighboring state.

It worked for Kerry. Yet Romney now faces a pitched battle there against not only Huckabee but also McCain, who, more than any other Republican, has been campaigning intensely in New Hampshire to win back the independents and party faithful who rallied around his banner in 2000.