Here are a few points from the Catechism I have for limitations on retribution (and haven’t gotten very far):
The Catechism at 2266 seems to suggest a prosecutor is duty bound ("right and duty to inflict punishment proportionate to the gravity") to try and get a retributive sentence that is commensurate to the crime when a punishment is sought (which seems to say they are duty bound not to go for anything more or less; they must seek an eye for an eye). Retribution also appears to be the “primary aim” of punishment. Furthermore, in seeking this commensurate retribution, the prosecutor needs to try and keep in mind (amongst those choices available) which is best capable of rehabilitating the particular criminal, for the very sake of his brother he is punishing. In a sense, the prosecutor needs to seek the good of the criminal.
The Catechism at 2267 seems to suggest non-lethal means of punishment better promote human dignity, and that it not be used unless there is a significant threat that person’s continued life poses upon society. Therefore, it appears possible that the punishment is not commensurate with the crime and yet must be the punishment if this limitation is met. Thus, retribution may be limited by considerations such as these. However, one could read the text “…to defend and protect people’s safety from the aggressor, authority will limit itself to such means…” as not really placing this limitation since “safety” may include more than just physical health, and may include their spiritual health. Arguably the “people’s safety” might be jeopardized, as a people, if their society is one that does not seek just retribution. However, this does not seem to hold much water since the text says “protect people’s safety from the aggressor” and here the potential threat would not be coming from the aggressor, but rather the prosecutor. Furthermore, mercy and respect for human life are surely necessary to the spiritual health of the people. Finally, I have seen 2267 being challenged as non-binding by some respectable people like Justice Scalia. At first I deemed such an opinion like that as outright heretical, but after reading more I am now inclined to retract such an accusation (I think that requires me studying what is actually binding and what is not).
So with these passages it seems that retribution is the primary objective of any punishment. It seems there are some limitations (2267) but at the same time it seems to suggest the prosecutor is duty bound to bring about retribution when punishing (2266), which seems to produce an apparent contradiction. However, even with 2267 aside, surely it is not the case that the government ought to always seek retribution in every case. Practical concerns surely factor in, and, added to that, it would seem that since the government is one of the servants of God’s Wrath (Romans 13:4), it may also display mercy as God is merciful. Furthermore, there is the good company of St. Thomas Aquinas who thinks that not all things should be outlawed in the first place, which means no punishment for some wrongs, which means no commensurate punishment for some evils. My thought is that perhaps that the “duty” spoken of in 2266 is a qualified one.
What then are the specific qualifications? If the qualifications are to punishment itself, how are they compatible with retribution being the “primary aim”?
Though I have few answers for the first question, I could at least see an answer to the latter question. Non-retributive qualifications to punishment could be compatible with retribution being the primary aim of punishment, just like avoiding certain foods for concerns other than nutrition is still compatible with the primary aim of eating being nutritive (e.g. 1 Cor 8; eating certain food which external circumstances may produce sin). (Note: So it would at least appear 2267 is compatible with 2266).
