WATCH: How 2018 midterm election results reflect the nation's division

WATCH: How 2018 midterm election results reflect the nation's division
  • Now Playing: ABC News’ Jonathan Karl breaks down key midterm races



  • Now Playing: The 2018 Midterm Elections Forecast on FiveThirtyEight.com



  • Now Playing: Sen. Kevin Cramer said failure to ban late-term abortions inspired him to run



  • Now Playing: How 2018 midterm election results reflect the nation’s division



  • Now Playing: Sen. Joe Manchin expected to win re-election



  • Now Playing: Ron DeSantis to become Florida governor after Andrew Gillum concedes



  • Now Playing: Democrats take control of the House



  • Now Playing: Democrats hope to win big after redistricting in Pennsylvania



  • Now Playing: Republican Kevin Cramer expected to defeat incumbent Heidi Heitkamp in North Dakota



  • Now Playing: Republicans will retain control of the Senate, ABC News projects



  • Now Playing: Ted Cruz expected to defeat Beto O’Rourke in Texas



  • Now Playing: Mike Braun pledges to ‘really make things happen in D.C.’



  • Now Playing: Marsha Blackburn to deliver victory speech after winning Senate race



  • Now Playing: Colorado’s Jared Polis on track to become 1st openly gay governor



  • Now Playing: Conor Lamb expected to win Pennsylvania House race



  • Now Playing: Sanders: ‘The president has had an incredible night’



  • Now Playing: Joe Donnelly gives concession speech



  • Now Playing: Meghan McCain reflects on first election since her father’s death



  • Now Playing: Floridians battle rain, lightning to cast vote in 2018 midterm



  • Now Playing: Andy Barr expected to defeat Amy McGrath for Kentucky House seat



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