Morning Joe 03/15/12

Poll shows some Romney backers wouldn't vote for Santorum

Top Talkers: A new Chicago Tribune/WGN-TV poll shows Mitt Romney and Rick Santorum in a statistical tie among the state's potential GOP voters. And a new Pew poll shows if Santorum is the GOP nominee, 20 percent of Romney supporters would likely vote ... more Duration: {{video.duration.momentjs}}