Now, as from the beginning, Jesus Christ calls his followers to be fearless victims of state-sponsored persecution, rather than complicit perpetrators in deadly structures of sin.
To use the threat of death is a ploy of the powerful, not of those who are meek and humble of heart. To throw convicted criminals to the proverbial lion is the work of empire-makers, not of Kingdom builders.
Jesus shocks his disciples--both yesterday and today--with a radical teaching to turn the other cheek when someone strikes you (Mt 5:39). Even more compelling than this teaching on non-violence may be Innocent Victim's command to Peter as he was being arrested: "Put your sword back into its sheath, for all who take the sword will perish by the sword" (Mt 26:52).
Even those who've done violence to others--from Moses and Saul to Alessandro Serenelli and beyond--should have an opportunity to encounter Divine Mercy. Cycles of violence can only be broken by Christian non-violence, that is, by a divine justice which transcends base desires for revenge. Otherwise, "righteous" vengeance will continue as a justification for further violence in perpetuity, and many will indeed perish by the same sword they have taken up.
Of course, the Catechism of the Catholic Church begins its teaching on this topic by stating that "the traditional teaching of the Church does not exclude recourse to the death penalty, if this is the only possible way of effectively defending human lives against the unjust aggressor" (n. 2267). But in a passage prophetically revised by St. John Paul II, the Catechism effectively closes the door on the death penalty in the 21st century with these two subsequent sentences:
"If, however, non-lethal means are sufficient to defend and protect people's safety from the aggressor, authority will limit itself to such means, as these are more in keeping with the concrete conditions of the common good and more in conformity with the dignity of the human person. Today, in fact, as a consequence of the possibilities which the stat has for effectively preventing crime, by rendering one who has committed an offense incapable of doing harm--without definitively taking away from him the possibility of redeeming himself--the cases in which the execution of the offender is an absolute necessity 'are very rare, if not practically non-existent'" (CCC, n. 2267).
From Jesus' personal witness, through the testimony of both Scripture and the living Tradition of the Church--including Catholic Social Teaching on the Death Penalty--the demise of the death penalty has officially arrived. It's obituary simply needs to be written, since the ongoing rationalization of such state-sponsored killing weakens the Christian resistance to other forms of brutality, such as legalized abortion and euthanasia.
To help the crucified and risen King kill death once again: Take the National Pledge to End the Death Penalty.