How has apocalypse—and Revelation in particular—been used in America during the 20th and 21st centuries? Contrary to conventional wisdom, apocalypse was not used by small persecuted groups to assure themselves that God would prevail in the end. Instead, it appears that apocalypse was used to create the appearance of a small, tightly knit group defined by a common belief. The danger these groups faced was not cognitive dissonance or the apparent absence of God, but social assimilation and the threatened loss of identity.

Horner's doctoral work in early Christian-Jewish relations has reshaped his understanding of modern forms of Christianity, leading him to investigate how apocalypse has been used since 9-11 to enhance Christian beliefs and literally "rally the troops." Horner seeks to understand how belief is used to build and maintain Christian communities and how the dynamics of belief play themselves out in the marketplace of society.