Mitt Romney, Rick Santorum lead President Obama in latest Rasmussen poll

With Rick Santorum and Mitt Romney adding to their primary wins Saturday, the latest Rasmussen poll shows both of them capable of posing a challenge to President Barack Obama in the November election.

According to Rasmussen's poll of likely voters, the updated numbers show Romney ahead by five points in a hypothetical 2012 battle with the president. While Romney sits at 48 percent to Obama's 43 percent, Santorum sits at 46 percent to Obama's 45 percent. His one-point lead over Obama is Santorum's second time ahead of the president.

Romney, Rasmussen reports, is the only other candidate to lead the president more than one time in the polls.

Obama's approval index history shows a swing in his approval numbers, from 44 percent strongly approving of the president's performance in January 2009, to 25 percent strongly approving now. The new numbers show that 44 percent strongly disapprove of the president's performance, up from 16 percent in January 2009. Obama's presidential approval index rating is -19.

Romney, who leads Santorum nationally by 12 points, faces multiple challenges in the coming week with primaries in Alabama and Mississippi on Tuesday. A Friday Rasmussen poll shows Romney with an 8-point lead over Santorum in Mississippi. In Alabama, Rasumussen has Romney, Santorum and Gingrich in a statistical tie.

For some, ideology and pragmatism are helping to pinpoint whom to vote for. Mississippi resident Jennifer Skipper told the Associated Press that her deciding factor in the primary is "how much I feel, personally, they can beat Barack Obama."

Mississippi governor Phil Bryant endorsed Romney Thursday, saying the U.S. "must have a Republican nominee who can defeat President Barack Obama and turn America around to get back on the right track."

The New York Times delegate counter shows that Romney's current count is more than double Santorum's, at 454 to 217. Newt Gingrich has 107 delegates and Ron Paul is fourth with 47.