PHOENIX — Opening arguments are scheduled Wednesday in a trial over allegations that two isolated towns on the Arizona-Utah line serve as the enforcement arm of a polygamous religious sect.

The trial is expected to reveal the inner workings of Colorado City, Arizona, and Hildale, Utah, and examine allegations that the towns systematically denied housing, water services and police protection on the basis of religion.

The case marks one of the boldest efforts by the government to confront what critics have said was a corrupt regime in both towns, where the dominant religion is the Fundamentalist Church of Jesus Christ of Latter Day Saints.

The communities deny the allegations and say religion isn’t a motivating factor in their decisions.