The Last Word with Lawrence O'Donnell 05/06/15

Rick Santorum to enter 2016 race on May 27

NBC News has confirmed Rick Santorum plans to enter the 2016 presidential election in three weeks. Lawrence takes a look back at Rick Santorum's first run to be the Republican presidential nominee in 2012 with David Frum, Anne Gearan, and Richard Wolffe. ... more Duration: {{video.duration.momentjs}}