I have always looked on the Catechism of the Catholic Church as a teaching aid towards catholic teachings. But Pope Francis' rewording of the Church's teaching seems to be in contradiction to the words of Pope St. John Paul II in his Gospel of Life (Evagelium vitae) which permits such an application in very limited circumstances.
- This is the context in which to place the problem of the death penalty. On this matter there is a growing tendency, both in the Church and in civil society, to demand that it be applied in a very limited way or even that it be abolished completely. The problem must be viewed in the context of a system of penal justice ever more in line with human dignity and thus, in the end, with God's plan for man and society. The primary purpose of the punishment which society inflicts is "to redress the disorder caused by the offence".46 Public authority must redress the violation of personal and social rights by imposing on the offender an adequate punishment for the crime, as a condition for the offender to regain the exercise of his or her freedom. In this way authority also fulfils the purpose of defending public order and ensuring people's safety, while at the same time offering the offender an incentive and help to change his or her behaviour and be rehabilitated. - EVANGELIUM VITAE
Since these words are from an encyclical and the rewording of Pope Francis on the subject of capital punishment are not, do Pope John Paul II encyclical letter holds precedence over the Catechism of the Catholic Church's wording as 2018?
Pope Francis does not seem to address the possibility that inmates can and have ordered the killing of innocent individual while being incarcerated. A few evil doers will almost always find a way to do evil even from prison. Just ask the Devil and he is equally incarcerated in hell. There are more cases in which moral theologians can see that incarcerations or even detention would not be advisable either in some emergency situations.
The death penalty
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.
Consequently, 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. - Vatican Press Office