Writing for Crisis Magazine, Christopher A. Ferrara asks the question “Can the Church Ban Capital Punishment?” He replies in the negative for very weighty reasons. In brief, the entire tradition of the Church advanced and defended the right of the State to resort to the death penalty, not only as a means to protect the citizenry from a repeat offense, but also for reasons of justice, deterrence, expiation, and even the spiritual welfare of the guilty, whose frightful sentence could lead to his conversion, as it has for many of the condemned.
Ferrara quotes the Catechism of the Council of Trent:
Again, this prohibition does not apply to the civil magistrate, to whom is entrusted the power of life and death, by the legal and judicious exercise of which he punishes the guilty and protects the innocent. The use of the civil sword, when wielded by the hand of justice, far from involving the crime of murder, is an act of paramount obedience to this commandment which prohibits murder. The end of the commandment is the preservation and sanctity of human life, and to the attainment of this end, the punishments inflicted by the civil magistrate, who is the legitimate avenger of crime, naturally tend, giving security to life by repressing outrage and violence.
Citing Pope Pius XII and Romano Amerio, Ferrara puts emphasis on the expiatory value of the sentence:
It must not be forgotten that the death penalty, like any criminal penalty, serves as a form of expiation. That is why prisons were once called penitentiaries. As Saint Thomas observes in the Summa: “Even death inflicted as a punishment for crimes takes away the whole punishment for those crimes in the next life, or at least part of that punishment, according to the quantities of guilt, resignation, and contrition; but a natural death does not.” (Cf. Romano Amerio Iota Unum, 435). Further, in the case of capital punishment the expiatory penalty reflects the sin of one whose grave crime has caused him to lose the right to life. Some 700 years after the Summa, Pope Pius XII repeated the constant teaching of the Church in this regard: “Even when it is a question of someone condemned to death, the state does not dispose of an individual’s right to life. It is then the task of public authority to deprive the condemned man of the good of life, in expiation of his fault, after he has already deprived himself of the right to life by his crime.” (AAS, 1952, pp. 779 et. seq)
What a lot of Catholics probably do not know is that Vatican City State and the other Papal States themselves formerly used the death penalty.
In the 19th Century, there existed in Rome the archconfraternity of San Giovanni Decollato (“Saint John Beheaded”), whose members did penance for those we now call death-row inmates. For them, part of being Christian also meant looking out for the spiritual welfare of the condemned. The Papal States were quite interested in man’s supernatural end, too. For this reason, execution days in Rome were days of prayer and penance.
Saint Vincent Pallotti used to work with the archconfraternity of San Giovanni Decollato, and never complained that the Popes, one of whom was Blessed Pio Nono, were “violating human dignity,” a claim that often comes from Catholics who oppose capital punishment in principle.
Granted, the State does not have to resort to capital punishment. The issue is may it do so. And the answer is yes.