Shattered Consensus: The Rise and Decline of America’s Postwar Political OrderBy James Piereson(Encounter, 389 pages, $27.99)  Authors of history books often design them with a unifying theme, a so-called theory of history. Henry Steele Commager, one of the most ardent…

The futile search for El Dorado, the city of gold, is the stuff of legends, among them a sardonic poem by Edgar Allen Poe about a knight who wasted his life in that pursuit. At first glance, the quest for…