What happens when a generation of art historians, schooled in the hagiography of modernism, turns its attention to art that is not modernist? To judge by the evidence of several recent exhibitions, they do well in certain limited channels, less well in others. In research and archival sleuthing, rigorous formal analysis, and use of social history, they are at their best. In appreciating the value or meaning of the art itself they are less certain, and are likely to turn to modernist criteria to validate art that they like. But in their understanding of American society and its commercial nature, and what this means for art, they are hopelessly at sea. And without their recognizing this, much of American art will remain in some fundamental way incomprehensible.

In the past two years New York has seen three major exhibitions of American realists. Presented at prestigious venues and bolstered by prodigious new researc ...