St. Augustine took the view that church authority conferred in the consecration and office of a bishop held true, even if the bishop's personal purity fell short of ideal. Such a bishop ought to do penance, but his acts as bishop were valid and carried the church's full authority. And the orders and authority of anyone ordained or consecrated by such a bishop were valid.

Another issue of church authority in the Donatist schism was the use of state interference to put down such a movement. Donatist extremists used force among their own people in order to keep them from returning to orthodox churches, and the Roman authorities opposed Donatists with violence. The North African church, including the Bishop of Hippo, came to condone this forceful interference. Augustine developed a theory of a "just war," based on this precedent together with the growing need to defend Roman cities against barbarian invasions. A war could be just if its purpose was noble, such as to achieve justice or peace. However, it must be led by appropriate authorities, and the principle of love exist despite the necessary killing. These ideas worked out by Augustine in response to Donatism and the times became enormously influential in the Middle Ages and after.*