The so-called ‘core four’ states are NC, FL, OH, and VA, and Santorum is leading Obama in each of those states, where as Romney is not:
RASMUSSEN – President Obama now trails former Pennsylvania Senator Rick Santorum by four points in a hypothetical 2012 matchup in combined polling of key swing states Florida, North Carolina, Ohio and Virginia. The president continues to hold a modest lead in those states.
Santorum leads the president 48% to 44% in the so-called Core Four states. Five percent (5%) prefer some other candidate in this matchup, and two percent (2%) are undecided. This marks a shift from last week, when the president was slightly ahead of Santorum.
Obama remains ahead of Romney 46% to 42%, showing no change from last week. Six percent (6%) prefer some other candidate in this matchup, and six percent (6%) are undecided.
The survey of 500 Likely Voters in Florida, Ohio, North Carolina and Virginia was conducted on March 10-15, 2012 by Rasmussen Reports. The margin of sampling error is +/- 4.5 percentage points with a 95% level of confidence.