The Mormon, Shaker, Mennonite or Quaker communities are examples, as are monasteries. The libertarian community of Modern Time was an example. This sort of structure tended to break down when economic factors turned against it. The sectarian communities were, by far, the most successful. In a sense, this is bad news for libertarians because a fundamental theme and strength of sectarian societies was the subordination of the individual to the collective.
Internal pressure refers to the problems societies faced as a result of their own organization.
External pressures refer to problems societies experienced from the U.S. government or from other more natural disasters. External threats to a community are more serious today than they were in the 19th centry. They put geographical distance between themselves and the government. As the government increased its reach, the Mormon lifestyle conformed to social pressures. Isolation is so often considered necessary because those who wish to set up a radically different society are always in the minority.