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 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.

The Democratic race showed virtually no change from last month. In the new AP-Ipsos national survey, New York Sen. Hillary Rodham Clinton has about a 2-to-1 lead over Illinois Sen. 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.

The poll involved telephone interviews with 1,009 adults nationally and was conducted from Dec. 3-5. It had an overall margin of sampling error of plus or minus 3.1 percentage points.