WASHINGTON — Mike Huckabee has vaulted from nowhere into second place in the Republican presidential race, riding a burst of support from evangelicals, Southerners and conservatives, a nationwide poll showed Friday.

The surge by the former Arkansas governor has come largely at the expense of Fred Thompson, according to the national survey by The Associated Press and Ipsos. Thompson has dropped after failing to galvanize the party's right-wing core as much as some had expected.

Rudy Giuliani remains the front-runner, yet while his support long has been steady it shows signs of fraying. Huckabee's growing strength in the South has come as the former New York mayor's support there has dropped, the poll found.

"Why not me?" Huckabee said in an interview Thursday. "I meet all the criteria. I'm conservative, but I think I appeal to a broader set of voters. And I think that people are also looking for someone with whom they can identify."

The poll showed Giuliani at 26 percent among Republican and GOP-leaning voters, about where he has been since spring. Huckabee has 18 percent, up from 10 percent in an AP-Ipsos survey a month ago and 3 percent in July.

Arizona Sen. John McCain has 13 percent, Mitt Romney 12 percent and Thompson 11 percent.

Huckabee's ascent in the national poll echoed his upswing in Iowa, whose Jan. 3 nominating caucuses will be the first votes in the 2008 presidential campaign. A recent AP-Pew Research Center poll showed Huckabee in a virtual tie there with Romney, the former Massachusetts governor, though Huckabee trails significantly in New Hampshire and South Carolina, two other important states that vote early next year.

A Baptist minister who mixes a folksy manner with an emphasis on his faith, Huckabee now has the support of 25 percent of white evangelical voters, 23 percent of conservatives and 28 percent of Southerners, the AP-Ipsos poll found. That is a solid increase in each of those areas since November, and a lead or share of the lead in each category.

"It's his humanness. He's not like a robot," said Natosha Romine, 24, a homemaker from Dallas and Huckabee supporter interviewed in the survey. "You could tell he's been through some stuff, like he's one of us."

The Democratic race showed virtually no change from last month. In the new AP-Ipsos national survey, Hillary Rodham Clinton has about a 2-to-1 lead over Barack Obama, 45 percent to 23 percent, with John Edwards at 12 percent, though a recent AP-Pew poll showed a three-way battle among them in Iowa.