Religious liberty has reemerged as a problem in liberal democracy. For guidance we can turn to James Madison. Unfortunately, his fundamental principle of religious liberty has been misunderstood. Madison believed that power over religious conscience always remains with the individual, which means that government never has a power to attempt to cause or prohibit religious opinions or profession and only has the power to prohibit religious practices that are “adverse to the rights of other citizens, or to the permanent and aggregate interests of the community.” Madison's fundamental principle of religious liberty is therefore that government has no “religious agency.” In matters of religious establishment, “no agency” means that government lacks even the power to cognize religious opinions or practices. But in matters of free exercise, “no agency” means that government can accommodate citizens’ religious consciences, even if that accommodation requires cognizing their religious opinions. An important but widely overlooked example of Madison's complex but principled approach to religious liberty is his 1790 proposal for a statutory exemption from federal militia service for religious objectors.