Thomas Aquinas, too, apparently could not raise himself above his times. In the Summa Theologica he poses the question of whether heretics can be endured, tolerated. And his answer is that heretics can not be tolerated. If it was just to condemn counterfeiters to death, then surely it was necessary to put to death those who had committed the far worse crime of counterfeiting the faith... The moral blindness, in certain respects, of even the holiest people should never be cause for surprise... It's a sign of maturity not to be scandalized.

source: Flannery O'Connor tags: Apologetics, History