The Democratic Primary isn't over - yet.

02:21

David Plouffe tells Lawrence O'Donnell that the race between Joe Biden and Bernie Sanders will be settled after next Tuesday's primaries - and then the party has to work on unifying. "We've got to work at it, we've got to listen to the Sanders supporters... we listen to those organizers on the ground, cause they've shown the ability to attract youth support, now we need to grow the turnout as well."