As the Republican Party careens toward civil war, Republican National Committee Chairman Reince Priebus got onstage to sing “Kumbaya” at the most recent debate in Miami. Claiming to speak not only for the Republican Party but also for “the conservatives, the Tea Party, our entire wonderful group of people,” Priebus promised that all would “come together and unify in Cleveland and get behind [our] nominee. That’s what we do as Republicans.” Indeed, that’s exactly what the Republican Party has traditionally done. Year after year, the party has told grassroots conservatives we have to fall in line and support whatever milquetoast...