"It seems to me that if one takes a position that human life is sacred in situations like Terri's or where abortion is concerned, one must logically also take the position that even a murderer's life is sacred, since even a murderer can find salvation (so long as still alive, anyway)."
Bulls**t! The Catholic Church's traditional support of capital punishment and opposition to abortion is completely and eminently sensible, not contradictory, if you open your eyes to the validity of the concept of human free will and personal responsibility. Murderers are guilty of intentionally heinous acts; the unborn, or physically and mentally infirm are innocent of any intentional crimes. Every Catholic used to know this. The fact that they don't today is another example of the abject failure of the American Catholic Church to perform its primary teaching function of the Magisterium. They don't teach traditional doctrine any more because it runs counter to the Marxist fetishism of the liberal elites, which are the only circles that today's Bishops really aim to please.
I am not a Catholic and my question was not raised in the context of Catholic dogma. Logically, if this is a question determined by free will, does not execution deprive the true criminal of any chance of exercise of free will by repenting and being saved? What about the prisoner convicted in error - is it not better to "err on the side of life" for these cases?