A new Public Policy Polling survey finds President Obama leading Mitt Romney nationally, 49% to 46%.
The running mate who helps Romney most — putting him in a 47% to 47% tie with Obama — is Chris Christie. Jeb Bush pulls Romney to within a point at 48% to 47% and Mike
Huckabee and Rick Santorum both get him to within two points at 48% to 46%.
Key takeaway: The
main positive effect of these potential running mates is to help Romney
shore up the Republican vote.

