The United States has a long history of religious pluralism, and yet Americans have often thought that people's faith determines their eternal destinies. The result is that Americans switch religions more often than any other nation. The Chance of Salvation traces the history of the distinctively American idea that religion is a matter of individual choice.

Lincoln Mullen shows how the willingness of Americans to change faiths, recorded in narratives that describe a wide variety of conversion experiences, created a shared assumption that religious identity is a decision. In the nineteenth century, as Americans confronted a growing array of religious options, pressures to convert altered the basis of American religion. Evangelical Protestants emphasized conversion as a personal choice, while Protestant missionaries brought Christianity to Native American nations such as the Cherokee, who adopted Christianity on their own terms. Enslaved and freed African Americans similarly created a distinctive form of Christian conversion based on ideas of divine justice and redemption. Mormons proselytized for a new tradition that stressed individual free will. American Jews largely resisted evangelism while at the same time winning converts to Judaism. Converts to Catholicism chose to opt out of the system of religious choice by turning to the authority of the Church.

By the early twentieth century, religion in the United States was a system of competing options that created an obligation for more and more Americans to choose their own faith. Religion had changed from a family inheritance to a consciously adopted identity.