Has American democracy's long, ambitious run come to an end? Possibly yes. As William G. Howell and Terry M. Moe argue in this trenchant new analysis of modern politics, the United States faces a historic crisis that threatens our system of self-government--and if democracy is to be saved, the causes of the crisis must be understood and defused. The most visible cause is Donald Trump, who has used his presidency to attack the nation's institutions and violate its democratic norms. Yet Trump is but a symptom of causes that run much deeper: social forces like globalization, automation, and...