Untrue.
All prospects of a negative outcome deter some. It is a truism. The death penalty, the most severe of criminal sanctions, is the least likely of all criminal sanctions to violate that truism.
25 recent studies finding for deterrence, Criminal Justice Legal Foundation,
cjlf.org/deathpenalty/DPDeterrence.htm
“Deterrence and the Death Penalty: A Reply to Radelet and Lacock”
homicidesurvivors.com/2009/07/02/deterrence-and-the-death-penalty-a-reply-to-radelet-and-lacock.aspx
“Death Penalty, Deterrence & Murder Rates: Let’s be clear”
prodpinnc.blogspot.com/2009/03/death-penalty-deterrence-murder-rates.html
“The Death Penalty: More Protection for Innocents”
homicidesurvivors.com/2009/07/05/the-death-penalty-more-protection-for-innocents.aspx
Please review:
“Death Penalty Cost Studies: Saving Costs over LWOP”
homicidesurvivors.com/2010/03/21/death-penalty-cost-studies-saving-costs-over-lwop.aspx
“Duke (North Carolina) Death Penalty Cost Study: Let’s be honest”
prodpinnc.blogspot.com/2009/06/duke-north-carolina-death-penalty-cost.html
(NOTE: There is a newer study out, by one of these authors, that finds NC MIGHT save $11 million by ending the death penalty, or 1 penny every three days/person. I have not read it, yet.Based upon the prior study the death penalty is cheaper.)
Cost Savings: The Death Penalty
homicidesurvivors.com/2009/05/07/cost-savings-the-death-penalty.aspx
It has been Catholic teaching for nearly 2000 years.
Until you, no one in this discussion has questioned that man has been authorized by God to take lives under certain circumstamces. Men taking the lives of other men has been morally licit under God’s law for what, 7000 years.
I think you give way too much deferrennce to popular culture and not to Catholic teaching, which makes the clear distinction between the morally licit death penalty, in accordance with the sanctity of life, but always comdemns abortion as an intrinsic evil.