The founders of the United States deemed moral citizens essential to the perpetuation of the republic, yet they created a secular national government that lacked any power to regulate morality. Ensuring a virtuous population became primarily the responsibility of the churches and reform groups that relied not on coercion but on moral suasion. Some states did regulate various forms of personal morality, but only on very rare occasions before the Civil War did Congress pass moral legislation.

That changed after the war because the Christian lobby convinced the federal government to accept a far greater role in regulating moral behavior. . . . Giving appropriate attention to the role played by conservative Christians adds complexity to the historical narrative of the creation of the twentieth-century state.

Gaines M. Foster, Moral Reconstruction: Christian Lobbyists and the Federal Legislation of Morality, 1865-1920, 6.