"Government has no more to do with the religious opinions of men than it has with the principles of mathematics....Let every man speak freely without fear, maintain the principles that he believes, worship according to his own faith, either one God, three Gods, no God, or twenty Gods....Let government protect him in so doing." Baptist minister John Leland penned these famous words in 1776. They are reprinted in The Writings of John Leland (1969), edited by L. F. Greene. During his campaign for the presidency in 1800, Thomas Jefferson (1743–1826; served 1801–9) quoted Leland's words.

Religious freedom is a pillar of individual liberty in America. But while the pillar stood firm in early America, views of religious freedom slowly evolved in the 1600s and 1700s. When settlers first journeyed to the New World's eastern shores in the early 1600s, religious freedom meant freedom to establish...