I think you see the issues properly.  I also doubt that the death penalty, as presently prescribed in the US, has much to do with either preventing or contributing to the large numbers of homicides that plague American society.  In order for it to have much preventative effect, if in fact it ever would, it would likely have to be pursued with such a vengence (no pun intended) that would allow even less care and attention to due process.  That said, with the exception of scattered instances, I don't see Americans as taking much joy from executions.

In situations like this I like to remind myself, and others who will listen, of those who have paid the ultimate price for society's shortcomings, the horrifyingly large numbers of our fellow man who have become the victims of senseless killings. We owe them more than casual mention.

I can swear there ain't no heaven but I pray there ain't no hell. _ Blood Sweat & Tears