A Flock of Fools, by Pamela Kennedy

As each day went by the obvious became more obscured. His eloquence captivated his audience wherever he went. Tantalizing promises of abundance, wealth, and security couldn't be resisted.

"I need your help," he implored his followers. "Seek out those who do not share our vision..."

Neighbors spied on each other in casual ways. Opinions opposing the Council were reported as well as actions contradicting the "approved behavior". Neighborhoods became smaller as the unfaithful were moved away to an undisclosed location. There seemed to be no ending to this insanity.

It could only have ended when his followers stopped following him.