Victor Davis Hanson is a classicist and historian at the Hoover Institution, Stanford University. His new book, The Savior Generals, is just out from Bloomsbury Press.

By a.d. 200, the Roman Republic was a distant memory. Few citizens of the global Roman Empire even knew of their illustrious ancestors like Scipio or Cicero. Millions no longer spoke Latin. Italian emperors were a rarity. There were no national elections.

Yet Rome endured as a global power for three more centuries. What held it together?...

As long as the sea was free of pirates, thieves were cleared from the roads, and merchants were allowed to profit, few cared whether the lawless Caracalla or the unhinged Elagabalus was emperor in distant Rome.

Something likewise both depressing and encouraging is happening to the United States. Few Americans seem to worry that our present leaders have lied to or misled Congress and the American people without consequences....