Long before Trump’s arrival on the scene, it was conservative radio talk show host Michael Savage, the idealogical godfather of “Trumpism,” who galvanized this insurgency. Savage gave it a voice and a powerful narrative, one that proved extremely helpful to those, like iconoclastic Senator Ted Cruz, who rose to prominence taking on the very same GOP beltway insiders that Donald Trump is now making so nervous. Years before Trump, Savage had already redefined the nature of the American political landscape when he blew up the Republican Party establishment’s hold on its working class base. Trump can come or go, but...