Regardless of current efforts to change that, as this article from Roberto de Mattei explains.
Whoever says death penalty is evil in itself ‘falls into heresy’: Church historian
The lawfulness of the death penalty is a truth de fide tenenda, defined by the ordinary and universal Magisterium of the Church, in a constant and unequivocal manner. Whoever affirms that capital punishment is in itself an evil, falls into heresy.
The teaching of the Church was clearly expressed in a letter dated December 18, 1208, in which Innocent III condemned the Waldensian position with these words, reported by Denzinger:
“De potestate saeculari asserimus, quod sine peccato mortali potest iudicium sanguinis exercere, dummodo ad inferendam vindictam non odio, sed iudicio, non incaute, sed consulte procedat” (Enchiridion symbolorum,definitionum et declaratium de rebus fidei et morum, edited by Peter Hünermann S.J., n. 795).
That is: “With regard to the secular power, we affirm that it can exercise a judgment of blood without mortal sin, provided that in carrying out the punishment it proceeds, not out of hatred, but judiciously, not in a precipitous manner, but with caution.” (Innocent III, DS 795/425).
The same position was reaffirmed by the Catechism of the Council of Trent (Part III, n. 328), by the Major Catechism of Saint Pius X (Part III, n. 413) and by the new Catechism of the Catholic Church (n. 2267). Pope Francis has now signed a rescript which modifies the Catechism with this new formulation:
“The Church teaches, in the light of the Gospel, that ‘the death penalty is inadmissible because it is an attack on the inviolability and dignity of the person,’ and she works with determination for its abolition worldwide.”
According to the prefect of the Congregation for the Doctrine of the Faith, Cardinal Luis Ladaria, the new text follows in the footsteps of the teaching of John Paul II, in the encyclical Evangelium vitae, but there is a radical difference. John Paul II, in Evangelium vitae, holds that the Church, in the current historical circumstances, ought to favor the abolition of the death penalty, but he affirms that the death penalty is not unjust per se, and the commandment “You shall not kill” has absolute value only “when it refers to the innocent person” (nos. 56-57). Pope Francis instead considers capital punishment inadmissible in itself, openly denying a truth infallibly defined by the ordinary Magisterium of the Church.
To justify this change, an appeal is made to changed sociological conditions. In Pope Francis’ rescript, it says:
“Recourse to the death penalty on the part of legitimate authority, following a fair trial, was long considered an appropriate response to the gravity of certain crimes and an acceptable, albeit extreme, means of safeguarding the common good.Today, however, there is an increasing awareness that the dignity of the person is not lost even after the commission of very serious crimes. In addition, a new understanding has emerged of the significance of penal sanctions imposed by the state. Lastly, more effective systems of detention have been developed, which ensure the due protection of citizens but, at the same time, do not definitively deprive the guilty of the possibility of redemption.”
However, the notion of “human dignity” does not change depending on historical times and circumstances, just as the moral significance of justice and punishment does not change. Pius XII explains that when the State resorts to the death penalty, it does not claim to be the master of human life, but only recognizes that the criminal, through a kind of moral suicide, has deprived himself of the right to life. According to Pope Pius XII:
“Even when it comes to the execution of one sentenced to death, the State does not dispose of the individual’s right to life. It is then reserved to the public authority to deprive the condemned of the ‘good’ of life, in expiation of his fault, after he has deprived himself of his ‘right’ to life for his crime. (Address to Participants in the International Histopathology of the Nervous System Conference, Sunday, September 14, 1952, n. 28)”
For their part, theologians and moralists over the centuries, from St. Thomas Aquinas to St. Alphonsus de Liguori, have explained how the death penalty is justified not only by the need to protect the community, but also has a retributive character, in that it restores a violated moral order, and an expiatory value, as with the death of the Good Thief, which united him to the supreme sacrifice of Our Lord.
Pope Francis’ new rescript expresses that theological evolutionism, condemned by Saint Pius X in Pascendi, and by Pius XII in Humani generis, which has nothing to do with the homogeneous development of doctrine treated of by Cardinal John Henry Newman. The condition for the development of dogma is, in fact, that the new theological statements do not contradict the previous teaching of the Church, but limit themselves to making it explicit and deepening it.