John Courtney Murray's theory on contemporary church-state relations posits four transtemporal principles: the duality of church and state, the freedom of the church, the freedom of the state, and the necessity of their cooperation for the human good. He argued that a just society requires a separation of church and state but also their harmonious working relationship, with the state ensuring public order (peace, morality, justice) and the church providing moral and spiritual guidance, ultimately grounding these principles in the natural rights of the human person. His work, most notably articulated in We Hold These Truths and influential in the Second Vatican Council's Declaration on Religious Freedom, reconciled traditional Catholic social teaching with modern democratic principles by finding common ground in natural law and universal human dignity.