2020 moderator breaks down tonight?s debate

In a special pre-debate edition of Battleground, S.E. Cupp breaks down the high-stakes showdown between Kamala Harris and Donald Trump that could reshape the race for the White House. With new polling showing dead-heats in critical swing states, we examine Harris' surprising strength in North Carolina, the fight for McCain Republicans in Arizona, and skyrocketing voter registration that could upend the electoral map. Finally, a moderator from Kamala Harris?s 2020 vice-presidential debate weighs in.