This thesis probes the conceptual and practical limits of toleration by exploring theories that address how modern liberal states should cope with religiously extreme minority groups in the light of a concrete case, that of The New Jerusalem, a self-contained theocratic community in modern-day Mexico. The thesis analyses some implications of the case for understanding how modern liberal states ought to deal with illiberal religious groups that do not respect some fundamental rights of their members. It questions whether the theories and prescriptions of influential recent liberals and their critics, such as Kukathas, Kymlicka, Balint and Ayelet Shachar are adequate to protect either the rights of minority groups or the rights of individuals within communities that tend to oppress their vulnerable members. The thesis seeks to elucidate difficulties with these theories by setting them against the reality of The New Jerusalem. Placing theory in conversation with practice, it concludes that, though frequently disregarded in liberal literature, moral compromise addresses several of the same questions as political toleration, and that it could work alongside policies of toleration and differentiated treatment to reach long-lasting agreements where profound differences between individuals and communities make consensus difficult to attain