The Native American Church is a syncretic spiritual group whose beliefs are constructed from Protestant Christianity and traditional Native American religious ceremonies, mainly from the tribes of the Plains, the Great Basin, and the Southwest. It was founded in 1918, and has a membership which probably ranges into the hundreds of thousands. It incorporates the ritual use of peyote in their ceremonies, and are the only religious group in America allowed an exemption to Federal drug laws for the purposes of their beliefs.
The reasons for this actually have more to do with lingering questions of native sovereignity than the First Amendment, and while anybody of Indian descent can join the Church, legally speaking only enrolled members of a recognized Native tribe are allowed to use peyote. This is the government's reason for allowing the Native American Church to use peyote, but not allowing, say, Rastafarians the freedom to smoke marijuana.
In particular because of their exemption from these drug laws, the Church has been subject to a great deal of interest and attention by Westerners, usually for ostensibly spiritual reasons. Because of this, the Church has gradually withdrawn from its non-tribal contacts, and is now very, very difficult for a non-Indian to get in touch with. | 
