 The former president who just days ago said he wanted to focus on this message of unity, now calling President Biden the worst president in American history, insisting whoever the left puts up will be more of the same. As for Harris's running mate, here's former New Jersey governor and ABC News consultant Chris Christie. Josh Shapiro would be the first person on my list if he has approval ratings in the high 60s in Pennsylvania. If he could deliver Pennsylvania, that allows them to play in Michigan, Wisconsin, Arizona.