Now ask this question: In this rebirth of the United States, in this American renaissance, who proved truly indispensable? Who passed Sidney Hook's test? My own list includes just three names: For giving conservative principles unassailable academic rigor, Milton Friedman. For deploying these principles in the realm of practical politics, Ronald Reagan. And for introducing conservatism into public discourse—insistently, unapologetically, and with utterly irresistible bravura—William F. Buckley, Jr.