KEVIN PHILLIPS, a keen analyst of American politics, is also a historical sociologist in the best sense of the term. The ways in which our society is both constituted and divided, not only in the present but as a consequence of history, have long been his concern. Early in his career, this steered him toward the changing composition of the electorate, and thus toward those elections that reveal significant shifts in the demographic alignments that drive American politics. His insightful debut, The Emerging Republican Majority (1969), analyzed the conservative realignment that increasingly drove Republican politics from the Nixon era to Bush the Younger in just those terms. Whether that era is now ending has become the burning question of the past few weeks—and one might hope that Phillips will return to this subject in his next book.

In 1775, however, Phillips deals with political loyalties more fundamental than the mere matter of party allegiance. His broader purpose is to write a sketch of American nationalism at the revolutionary moment when that concept first cohered. That nationalism is not predicated on the egalitarian ideals of 1776, eternally expressed in the Declaration of Independence: 1775 is manifestly an anti-1776 book. The essential argument of Phillips’s book is that most of the developments that really mattered had already taken place, and that a fixation on Jefferson’s airy platitudes will prevent us from grasping how much had already been accomplished. The more authority we ascribe to the Declaration, Phillips posits, the more difficult it becomes to understand the broader array of factors that united some Americans and divided them from others. But this insistence on the primacy of 1775 as “the pivotal year” creates more problems than it solves....