Separation Without Neutrality Being Simple

Even within a single country holding the principle formally, separation of church and state generates ongoing and often contested boundary disputes rather than a single settled line, since almost every modern state that separates religious and political institutions still funds religious schools to some degree, exempts religious organizations from certain taxes, or accommodates religious practice within otherwise general law, arrangements defenders describe as consistent with separation and critics describe as its erosion.

American constitutional law has developed and revised several competing tests over the twentieth and twenty first centuries for where the line between permissible accommodation and impermissible establishment falls, reflecting genuine and unresolved disagreement rather than a single doctrine simply being applied. The principle also coexists, sometimes uneasily, with the free exercise of religion it is meant to protect, since laws neutral on their face can burden particular religious practices, requiring courts and legislatures to weigh separation and free exercise against each other in specific cases rather than treating either principle as absolute. This atlas records separation of church and state as a widely shared constitutional principle whose concrete meaning and required distance vary substantially by country and by era.