Steve Kornacki explains how Joe Biden rebuilt the 'Blue Wall' and won the presidency

04:33

Steve Kornacki joins Andrea Mitchell to discuss how support from the cities and suburbs in the battleground states of Michigan, Wisconsin and Pennsylvania helped Joe Biden rebuild the "Blue Wall" of long time Democrat-won states that flipped to Trump in 2016, and checks in on the vote counts in Georgia and Arizona, both of which remain too close to call.