MSNBC Live with Tamron Hall 12/18/15

Will DNC penalty hurt Bernie Sanders campaign?

One day before the third and final Democratic debate of the year, the Bernie Sanders campaign is being punished after a staffer improperly accessed details on supporters collected by the Clinton campaign. NBC’s Kristen Welker and MSNBC’s Steve Kornacki takes a closer look at how this could hurt Sanders in the final weeks before first votes are cast in Iowa and New Hampshire where the race is tight. ... more Duration: {{video.duration.momentjs}}