This article examines the relationship between the painters Frederic Edwin Church and Martin Johnson Heade, and the author Theodore Winthrop at a time when all three were tenants of the Tenth Street Studio building in New York City and Church was completing his important painting, The Heart of the Andes (1859). The article examines the close intellectual relationship between Church and Winthrop, who wrote a pamphlet to explicate Church's painting. The association of Winthrop's ardent nationalism and belief in American expansionism with this understanding of art as a moral practice is analysed and related to current interpretations of mid-century landscape. A discussion of Winthrop's 1861 novel, Cecil Dreeme, as a fictionalized account of the complexity of debates in the Tenth Street Studios leads into an analysis of The Heart of the Andes, which identifies complexities and ambivalences in the painting that put it partly outside the moral position. A comparison of The Heart of the Andes and Heade's 1859 painting Approaching Thunderstorm suggests Heade's opposition to Church's work as moral example. The article concludes by situating these positions and debates within influential accounts of US culture after the Civil War and arguing that the three-way conversation between its protagonists that began in 1859 exemplifies some of the tensions characteristic of attitudes to the arts in the society that went to war.