On the heels of a tumultuous Republican convention, Hillary Clinton hopes her gathering in Philadelphia will show off a forward-looking Democratic Party united behind her steady leadership. But to do that, she must overcome lingering bitterness among supporters of defeated rival Bernie Sanders and a political mess and last-minute leadership shake-up of the party's own making.
02:02Sen. Tim Kaine is using his debut appearance as Hillary Clinton's running mate on Saturday to introduce himself to voters. He offered a tough assault on Donald Trump, and then added that Clinton is the opposite of him.