Donald Trump has changed the rules of campaigning. In no area has he done more pioneering work than in the field of insults. He has insulted countries, political opponents, senior Republican leaders, and entire classes of people—from Mexican immigrants to POWs. So it would be reasonable to expect that when he takes the center lectern next week for the first Republican debate, he’ll continue true to form—a knee to the groin here, a sweeping denunciation there. The word stupid is no doubt already limbered up and bouncing around his verbal ready-room.