 Ambassador Nikki Haley and Florida Governor Ron DeSantis will speak in support of the new Trump Vance ticket. It's Tuesday, July 16th, and this is All Things Considered. I'm Juana Summers. And I'm Elsa Chang. Little is publicly known about the ideology of the gunman who fired at former President Trump at a campaign rally. But extremism experts say there have been signs that things were building to this moment.