Thirty percent of Republican primary voters said they support Santorum for the party's nomination, 3 percentage points ahead of Romney, but still within the margin of error, results of the CBS News-New York Times poll released Tuesday indicated.
On Monday, a Pew poll had Santorum,a former U.S. senator representing Pennsylvania, ahead 30 percent to 28 percent, but a Gallup poll showed Romney, the former Massachusetts governor, ahead 32 percent to 30 percent. However, both were in the polls' margins of error, so the races were in a statistical dead heat.
The two other major candidates, U.S. Rep. Ron Paul of Texas and former House Speaker Newt Gingrich, were well behind at 12 percent and 10 percent.
Santorum's bump is fueled by increased support from self-described conservatives, evangelical Christians and Tea Party supporters, results indicated.
However, the poll also pointed up the race's fluidity. Six in 10 voters who listed a preferred candidate indicated they could change their mind.
Results are based on nationwide telephone interviews conducted with 331 Republican caucus or primary voters conducted Wednesday through Monday. The margin of sampling error is 5 percentage points.