DES MOINES, Iowa -- Mike Huckabee rode to a sweeping victory in the Iowa caucuses on a foundation of support from fellow evangelicals -- but Christian conservatives don't explain the whole Huckabee story.

The former Arkansas governor rose from relative obscurity to win the opening contest for the Republican presidential nomination largely by striking a chord among heartland voters with his authenticity and populist message.

He campaigned on a common-man theme that hope and optimistic matter most, upsetting wealthy rival Mitt Romney, the former Massachusetts governor who spent millions to boost his profile, turn out voters and go after Huckabee with television ads.

"People really are more important than the purse," he told about 300 supporers at a hotel in Des Moines. "Tonight, we proved that American politics is still in the hands of ordinary folks like you and across this country who believed that it wasn't about who raised the most money, but who raised the hopes, dreams and aspirations for our children and their future.

"Tonight," he added, "I hope we will forever change the way Americans look at their political system and how we elect presidents."

Huckabee maintained that he has been outspent at least 15-to-1. With 87 percent of precincts reporting, he finished with 34 percent, ahead of Romney with 25 percent.

But he told FOX News Thursday he expects a windfall of contributions now that he's proved his campaign is viable.

"This is not just an Iowa thing. We're not a one-state wonder," he said, responding to a common criticism from the Romney campaign, which claims that unlike Huckabee it is running a nationwide race.

Huckabee will likely now expand his populist message to emphasize fair trade, a tough-but-compassionate approach to illegal immigration and the "fair tax," which would replace income taxes with a 23 percent sales tax.

Those are among the things Huckabee will use to cast himself as the outsider against Arizona Sen. John McCain, who is polling with Romney at the top in New Hampshire.

As one aide put it, "This is a big wave, we can surf anywhere now."

But Huckabee faces a tougher challenge in Tuesday's New Hampshire primary, where the campaign knows voters are more secular.

Romney has spent more time there and is better-known, being from neighboring Massachusetts. Huckabee began running television commercials there two weeks ago.

Huckabee, a Southern Baptist minister before entering politics, was relegated to also-ran status when he started campaigning nearly a year ago in Iowa.

He was considered a favorite of evangelicals, but as a former small-state governor sometimes at odds with the GOP establishment, Huckabee was dismissed as someone who couldn't assemble the money and organization needed to win.

In August, his surprisingly strong second-place finish in the Iowa straw poll helped him begin to shed that image and start a slow ascent in state polls. At the straw poll, Huckabee was aided by supporters of the "FAIR tax."

Meanwhile, Romney's first-place finish in the straw poll was written off as expected since better-known rivals Rudy Giuliani and John McCain had decided to skip the contest.

Huckabee enlisted national evangelical Christian leaders to help him rev up Iowa pastors and churchgoers and began running TV ads defining him as a Christian conservative. By December, he had surged ahead of Romney, whose Mormon faith made many evangelicals uncomfortable.

Evangelicals helped Huckabee come in first, according to entrance interviews by The Associated Press and the television networks. More than half of GOP voters said they were born again or evangelical Christians, and nearly half of those supported Huckabee. Among non-evangelical voters, Romney led by at least 2-to-1.

More than a third of Republicans said it was important to have a candidate who shared their religious beliefs, and a majority favored Huckabee. The former Arkansas governor also performed strongly among those who identified themselves as very conservative.

Romney managed to narrow the gap in polls by running negative spots about Huckabee's record on taxes, illegal immigration and clemency for criminals. But it wasn't enough.

Earlier this week, Huckabee said he would respond to Romney with attack ads of his own, then changed his mind and pulled the commercial. He still played the spot for the media, ostensibly to prove he had really made it.

Huckabee's conservatism has a softer edge; he often says he is conservative, but he is not mad about it.

"It's not hating those who are in front of us," he said Thursday. "It's loving those who are behind us."

FOX News' Carl Cameron and The Associated Press contributed to this report.