Most of the great theologians have defended the principle of capital punishment. We're in danger of forgetting why

The death penalty should be discontinued in the US. It is administered unjustly based on a person’s socioeconomic status. I expect most Catholics would agree with that. But many commentators, academics and bishops – now perhaps even Pope Francis – want to go further: they say that the death penalty must always and everywhere be considered immoral. The trouble is that Catholic theology has generally supported the idea of capital punishment, for reasons which are perennially valid.

Historically, Catholic theologians have given three main arguments in favour of the death penalty. The first is that justice demands it for certain offences. Every injustice creates an imbalance, and justice, say the theologians, demands that the imbalance must be corrected.

Second, the Church has taught that the death penalty is expiatory. Expiation is an attempt to redress, through penance and other forms of mortification, some wrongdoing. Catholics are taught that we must achieve expiation either here or in the cleansing fire of purgatory.

As Pope Pius XII said: “It is reserved then to the public power to deprive the condemned man of the benefit of life, in expiation of his fault, when already, by his crime, he has dispossessed himself of the right to life.”

Third, the death penalty can sometimes support the common good. St Thomas Aquinas makes this point: “Therefore if a man be dangerous and infectious to the community, on account of some sin, it is praiseworthy and advantageous that he be killed in order to safeguard the common good.”

It is no coincidence that the increasing rejection of the death penalty has coincided with a decline in religious practice and belief in an afterlife. If there is no God, and no punishment or purgation in the afterlife, then there is no need for expiation, and injustice becomes not a cosmic imbalance with implications that spread to eternity but a simple transaction payable only in this one terminable lifetime.

Even Catholics can easily forget about expiation: it’s rare that we hear about purgatory and its pains, never mind being instructed to offer up our suffering for the souls in purgatory.

The traditional teaching that the death penalty is legitimised by justice and expiation has not changed simply because of the passage of time. But today, the Church’s traditional doctrine is presented as though it hinged on deterrence or simple physical protection of the public.

The current Catechism, for instance, says that the death penalty is licit “if this is the only possible way of effectively defending human lives against the unjust aggressor.” The Catechism also says that the modern state has made the death penalty, de facto, practically illicit; and that the state should punish a criminal without “taking away from him the possibility of redeeming himself”.

This fails to engage with the tradition which runs from the Old as well as the New Testament (Romans 13:4 for instance) to Augustine to Aquinas to the Catechism of the Council of Trent to Robert Bellarmine to the Vatican penal code – which until 1969 allowed for the death penalty for attempting to assassinate the Pope – to theologians today.

Although the Catechism obviously contains many infallible statements, some of its formulations are not infallible. A Catholic must give the Catechism due consideration when weighing moral issues, but when a difference arises, we must weigh the claims of the Catechism against those of the tradition. Indeed, Cardinal Joseph Ratzinger, when Prefect of the Congregation for the Doctrine of the Faith, stated: “There may be a legitimate diversity of opinion even among Catholics about waging war and applying the death penalty”. (He added that there was no such “legitimate diversity” over abortion and euthanasia.)

The trend in Catholic intellectual circles towards an absolute philosophical rejection of capital punishment goes too far. One sees, for instance, people comparing the death penalty to abortion. To conflate the situation of an unborn baby with that of a person guilty of a heinous crime, who is justly executed, is a category error of gross proportions.

I don’t believe the Church will ever magisterially teach that the death penalty is illicit, because I believe the Church is not free to do so. What I fear is that many Catholics will not stop at a practical call for prohibition in this or that instance, but will succeed – in the minds of the faithful at least – of removing from the moral imagination principles which have informed Catholic thought on criminal justice for almost two millennia.

In doing this, our leaders will not succeed in changing doctrine – it will remain safe, sequestered away in an unopened book somewhere in the Vatican – and the Church, however damaged, will survive. But the sensus fidei will have suffered another grievous injury.