Mitt Romney and Fred Thompson are tied for the lead in South Carolina's Republican Presidential Primary.

The latest Rasmussen Reports telephone survey finds both men earning 21% of the vote from Likely Primary Voters. That’s a big change from September when Thompson was on top with support from 24% and Romney trailed the frontrunner by nine percentage points.

Trailing the two leaders are Rudy Giuliani at 13%, Mike Huckabee at 12%, John McCain at 9%, and Ron Paul at 8%. Tom Tancredo and Duncan Hunter each earn support from 2% while 13% are undecided (see crosstabs).

Those numbers reflect a seven-point drop for Giuliani, a nine-point gain for Huckabee, little change for McCain, and a six-point jump for Paul.

Thompson, perhaps enjoying a boost from his recent endorsement by the National Right-to-Life Committee, leads among Evangelical Christian voters. Romney leads among other Protestants. Thompson leads among men while Romney leads among women.

Romney, in addition to his strong showing in South Carolina, leads the earliest voting states of Iowa and New Hampshire. Giuliani leads in Florida and in the national polls.

In South Carolina, as in other states, the race remains quite fluid. Sixty-eight percent (68%) of Romney’s supporters say they might change their mind before voting. For the other candidates, 47% to 57% of their supporters say the same thing.

Thompson is viewed favorably by 76% of the state’s likely primary voters, Giuliani and Romney by 72% each. For Romney, that’s a ten-point gain from the previous survey.

McCain continues to draw mixed reviews—60% favorable and 39% unfavorable. Huckabee is less well known—57% have a favorable opinion of him and 29% unfavorable. Ron Paul is viewed favorably by 35% and unfavorably by 50%.

Sixty-six percent (66%) of likely primary voters believe officers should check the immigration status of anyone they pull over for a traffic violation. Fifty-five percent (55%) say that illegal immigrants discovered through this process should be deported. Democratic primary voters are evenly divided as to whether such a policy would be a temptation to discriminate.

Seventy percent (70%) oppose drivers’ licenses for undocumented immigrants. Among all adults nationwide 77% are opposed to drivers’ licenses for undocumented immigrants.

Seventy-two percent (72%) say that President Bush is doing a good or an excellent job while 13% say fair and 14% say he is doing a poor job. Ron Paul leads among those primary voters who say the President is doing a poor job.

Seventy-five percent (75%) say that Governor Mark Sanford is doing a good or an excellent job. Sixteen percent (16%) say fair and 8% poor.

The Rasmussen Reports daily Presidential Tracking Poll is updated daily by noon Eastern.

See survey questions and top-line results. Crosstabs are available to Premium Members only.