IThis is moral issue and while the Church has NO authority over how a government applies it’s authority; just like the Church has NO authority over how a government applies it’s authority relative to abortion policy. Abortion is wrong is all case, the Death Penalty is not excluded as an option, but is wrong in virtually all cases… Same family of Pro Life teaching.
The teaching in the Catechism is clear. The references you make to a few bishops making comments carry a lesser weight than that an official Church teaching text. I see no references to prudential judgement, but instead a clear position which exerts the Church’s well established voice on moral issues.
Another Church teaching text on the subject… PSJPII’s EVANGELIUM VITAE. In this text (a small portion referenced below), the Saint Pope using clear, careful language which should deflate your contention that a Catholic’s outlook on the Death Penalty is a prudential judgement. Terms like ‘must’ are not really open to interpretation about the Church’s position.
56. 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. 47
It is clear that, for these purposes to be achieved, the nature and extent of the punishment must be carefully evaluated and decided upon, and ought not go to the extreme of executing the offender except in cases of absolute necessity: in other words, when it would not be possible otherwise to defend society. Today however, as a result of steady improvements in the organization of the penal system, such cases are very rare, if not practically non-existent._
In any event, the principle set forth in the new Catechism of the Catholic Church remains valid: “If bloodless means are sufficient to defend human lives against an aggressor and to protect public order and the safety of persons, public authority must limit itself to such means, because they better correspond to the concrete conditions of the common good and are more in conformity to the dignity of the human person”.48
I do not see how an informed Catholic could possibily support the death penalty today.