The UFC’s event at the White House was the perfect target for a terror attack: America’s elites, clustered around a small octagon in the open air for hours. A chaotic, packed city center. Plenty of cops and soldiers, to be sure, but then again, there are few defenses for a fast, deadly drone. As I sat through the event last weekend, I half expected something to go wrong. We seemed like sitting ducks, in a country that has amped itself up for political violence at every turn. Earlier this week,