Augustine himself, however, unlike Ambrose in Milan, was never an actual politician. He taught rhetoric that no doubt prepared lawyers and judges for public life, but it was a life which, at the end of his stay in Milan, he considered to be mainly empty and boastful. As a bishop he dealt, as we know from his letters and sermons, with many delicate political issues.
One of the most unsettling of these political issues was his dealings with the Donatists. Augustine’s later policies over the Donatists has merited for him an unduly harsh reputation among those who think it is a rather simple matter, in any polity, including a democratic one, to deal with fanatics. It is easy to criticize Augustine on the Donatist controversy if we think them to be merely pious dissenters.
In the beginning of this controversy, Augustine too thought that it was best to be tolerant and patient. Reluctantly, he found his kindly instincts ran stark up against the bloody reality he had to deal with. The theological issue in the light of the Donatist attacks necessarily required political attention. His fellow bishops and priests were being tortured, beaten up, killed, even. Augustine, then, is not the philosopher of the best state in this world, though he does have much to say about it. Rather he is the philosopher of the worst and those slightly less bad than the worst states — that is, most actual states in history.
Henry Paolucci put the issue as well as anyone:
“Doctrinaire libertarians are not likely to be persuaded by St. Augustine’s arguments supporting the view that, when civil governments are willing to do so, they have a right to compel heretics to enter the Church. Yet, upon close examination, these arguments (of Augustine) seem to stand up rather well as compared or contrasted with, say, President Lincoln’s views on compelling the rebellious Southern States to remain in the Federal Union, or the views of those who have justified the use of force to compel integration of the races in American schools, or of the separated provinces in the old Belgian Congo. St. Augustine pleads eloquently for mercy in the administration of civil laws, and demands of Christian public officials that they respect his pleas. Yet, at the same time, he warns all concerned with the maintenance of civil order not to undermine the foundations of society by attempting to ‘legalize’ or ‘legislate’ mercy.”