To write with urgency about the past is to write about the present, as every historian knows. This is certainly true for that speck of history that is American art. The first serious scholarship on colonial painting, for example, took place after the Great Depression had thrown modern capitalism into disrepute, and the eighteenth century seemed to offer a more benign model for American life. Likewise it was during the 1960s, when the prestige of modernism was plummeting, that Victorian art and all its forbidden pleasures began to beckon. So began the rehabilitation of such former pariahs as John Singer Sargent or Frank Furness, whose restored reputations now loom so large.

In our day, identity politics has become a central fact of American public life, and of art history as well. Whether this will prove in the end to be a good thing—i.e., whether the new insights gained will offset those lost along the way—remains an open ...