How big is Donald Trump's lead in South Carolina?

U.S. Republican presidential candidate Donald Trump speaks to supporters at a Pearl Harbor Day rally aboard the USS Yorktown Memorial in Mount Pleasant, South Carolina, December 7, 2015. REUTERS/Randall Hill
REUTERS

Two new polls show businessman Donald Trump leading the 2016 Republican presidential field in South Carolina, but there's still a question of how big that lead is.

A Fox News poll taken Saturday through Tuesday shows him 20 percentage points ahead of former neurosurgeon Ben Carson, who came in second place with 15 percent. But a Winthrop University poll taken November 30 through December 7 had trump up just 8 percentage points, with Texas Sen. Ted Cruz in second place with 16 percent.

Trump has 35 percent in the Fox News poll. And While Carson is in second place with 15 percent, Sens. Ted Cruz of Texas and Marco Rubio are close behind and within the margin of error, with 14 percent support each. All other candidates are in single digits.

The poll also found that Trump's proposal to temporarily ban all Muslims from entering the United States played well with South Carolina Republican voters. His support increased from 30 percent during the first two nights of the poll to 38 percent the last two nights after he released the plan.

He gets similar support from men (37 percent) and women (32 percent), although more support from older voters than younger ones. Thirty-eight percent of people over 45 picked him as their top choice, compared to just 39 percent of those under 45.

The Winthrop poll had Trump at 24 percent, with Cruz in second place at 16 percent. Carson is close behind in third place with 14 percent and Rubio with 11 percent.

All other candidates get less than 10 percent, although Bush is well ahead of the others with 9 percent support.

The numbers show that Trump's relative weakness with evangelical voters could prove problematic. He gets just 22 percent support among those who identify as evangelical Christians, but they make up nearly 60 percent of the state's GOP presidential primary electorate. Cruz and Carson are tied, with 17 percent support each among evangelicals, which is a significant drop from the 33 percent support he got from that group in a Monmouth poll a month ago. Other polling, including a CBS News survey from late November, show Cruz rising among evangelical voters as Carson has dropped in Iowa.

One in five evangelical voters remain undecided in South Carolina, the Winthrop poll found.

Although he's the hometown senator, Lindsey Graham doesn't see his presidential campaign gain much traction in South Carolina. In the Fox news poll, just 2 percent of supporters picked him as their preferred GOP nominee, and 18 percent said they would never support him for the nomination. He also got just 2 percent support in the Winthrop poll.

On the Democratic side, former Secretary of State Hillary Clinton maintains a strong lead in the state. She gets the support of 65 percent of Democratic primary voters, while Sen. Bernie Sanders, I-Vermont, gets just 21 percent. Former Maryland Gov. Martin O'Malley gets just 3 percent support.

  • Rebecca Kaplan

    Rebecca Kaplan is a political reporter for CBSNews.com.