In a fluctuating race, will Donald Trump’s reset succeed?

In light of his dip in the polls last week, Donald Trump attempted to reset his campaign on Monday by talking about economic policy. Meanwhile, both candidates have taken to questioning each other’s mental health, and a new competitor is poised to enter the race. Gwen Ifill speaks with Amy Walter of The Cook Political Report and NPR’s Tamara Keith for their analysis on the latest in the campaign.