Christopher Caldwell’s new book, The Age of Entitlement, offers a striking revision of recent American history that has the advantage of being readily summarized. The polarization of political opinion and the dissolution of the American fabric, he argues, has its roots in the passage of the 1964 Civil Rights Act, which represented a sharp break with the past. “The changes of the 1960s, with civil rights at their core,” he explains, “were not just a major new element in the Constitution. They were a rival constitution, with which the original one was frequently incompatible.” The common narrative surrounding civil rights,...