NASHVILLE - Former Sen. Rick Santorum of Pennsylvania has brought his national momentum to Tennessee, outdistancing Republican presidential rival Mitt Romney by a nearly two-to-one margin among voters taking part in a new Vanderbilt University poll.

But with Tennessee's GOP primary now just nine days away, the race here remains fluid because one in four potential voters says he doesn't know or doesn't like any of the candidates, said Vanderbilt political science professor John Geer.

"As big a theme as Santorum leading is that a lot of people haven't made up their minds," said Geer, co-director of the Vanderbilt Center for the Study of Democratic Institutions.

Santorum campaigned in Chattanooga on Saturday.

The center commissioned the survey of 1,508 registered Tennessee voters - including 815 who indicated a preference for a Republican candidate - Feb. 16-22, during the first week of early voting. The poll, conducted by Princeton Survey Research Associates International, had a 3 percent margin of error.

Poll participant Nick Mugavero, a retired industrial gas company executive who lives in Brentwood in southern Davidson County, said he has followed Santorum's career for years. While Romney isn't conservative enough for him and Gingrich "is not going anywhere" politically, Mugavero, 85, sees something deeper in Santorum.

"He's just a truthful guy," he said. "I know he's got problems now with some of the things he's said, but that's politics."

Santorum said during a debate in Arizona on Wednesday that he voted for the No Child Left Behind education law, which was championed by Republican then-President George W. Bush, even though it was "against the principles I believed in." Romney has attacked Santorum for the statement.

Geer said the race is fluid in part because voters don't know Santorum and his political weaknesses as well as they know Romney or Gingrich. The poll found just 25 percent of Republicans knew that Santorum, a two-term incumbent at the time, lost his 2006 Senate race by 18 points.

By contrast, 47 percent of Republicans knew Romney has a bank account in the Cayman Islands, and 54 percent knew that Gingrich had been punished for ethics violations by the House of Representatives.

Geer said pollsters started to see support for Romney picking up in the last few days of the survey.

Mary Martin, a professor who lives in Rutherford County and voted for Romney, said management experience is what matters right now.

"I swore never to vote for another congressman," she said. "That's not their experience. That's not the role they've played in government."

So if Santorum, Gingrich or Paul were the Republican nominee against President Barack Obama, Martin said she would have a tough choice to make.

But it wouldn't be a hard decision for Mugavero. He said he fundamentally disagrees with Obama's approach to governing, which he labeled "social engineering."

"I would vote for a mouse if that were the alternative," he said.

Geer said he expects most Republican voters to feel the same way, united by their desire to make Obama a one-term president even if they don't passionately believe in their party's eventual nominee.

For that reason, Geer said, he doesn't see Obama winning Tennessee, a reliably Republican "red state" where Obama lost by a large margin to Sen. John McCain of Arizona in 2008.