Kamala Harris switch scrambles Republicans as Trump resorts to insults

Donald Trump capped a tough week in which his Democratic opponents turned the tables, replacing aging Joe Biden with Kamala Harris as their top choice for president, by resorting to insults and extremism on the campaign trail.

A week ago, Trump was riding high on the iconic moment when he rose bloodied and with a defiantly raised fist from an assassination attempt, pulling away in the polls. Biden...