Examines how personal secularism shapes public opinion where we would expect it to matter: the line between church and state, or public secularism. We explore the nuances in Americans' attitudes on church–state separation, including how both personal secularism and nonreligiosity shape attitudes toward the twin religious protections guaranteed by the First Amendment, protection of religious free exercise and protection from government establishment of religion. Our analysis speaks directly to the current debate over the meaning of religious liberty.