Papa Benedetto has it right that every act of intentional abortion infanticide, euthanasia, etc. is unambiguously condemned because its intention is to kill an innocent human being, either as a means or as an end.
War is more complicated because it is a complex of actions which must be judged one by one AND as a totality. It is possible for a war to be just in its inception and in its intentions (defensive, limited, legitimately authorized, last resort etc.) but still contain elements that merit unequivocal condemnation. Acts of war deliberately directed against civilians, for example, present precisely the same moral problem as abortion: the deliberate shedding of innocent blood, which is abominable in the eyes of God.
The death penalty -- carried out justly by the legitimate authoities --- is not condemned as murder, but is justified (according to the Catechism) if it is essential to the protection of public safety.
Pope Benedict, like his predecessor John Paul, has insisted that in modern times, maximum security prisons make its possible to incarcerate murderers and other violent felons without possibility of parole, and in such a way that they are no longer a threat to society. They have advanced the teaching that if this is possible, then executions should be vanishingly rare.
I myself wonder about the situation where a person already serving a life sentence, re-offends: say, by attacking another inmate or a guard. This would suggest that even imprisonment didn't suffice to secure public safety in his case; and I suppose that's where the death penalty would become legitimate.
As a Catholic I am obliged to follow the teaching here, as well as I can understand it. Anybody want to read what it says in Evangelium Vitae and the Catechism, and offer a fuller interpretation?
BTW HOORAY, punching the air and high-fiving for Cardinal Egan. I always rejoice to see a vertebrate Bishop.
I have a HUGE problem with this line of reasoning. I believe murderers should be executed as punishment for their heinous crimes, not because society is unable to adequetely incarcerate them. Capital punishment is either right or wrong. The Catholic church seems to say society can only execute people when it can't contain them. Would this logic then allow pro-abortionists to say babies can be aborted when thier mother's can't afford the children? Possibly.