I actually ended up against the death penalty on logical, not moral, grounds. I was not sure how I felt about it morally, especially given the era when they were letting a lot of pretty bad criminals out of prison who ended up reoffending in even worse ways. I could see how people would want the death penalty just to make absolutely sure that Joe Serialkiller wasn’t going to be out on the street again in 10 years terrorizing somebody else. Which is the main reason most people support the death penalty. They don’t trust the system to keep the guy locked up.
But when I saw how messed up the death penalty process was in USA and how people who should probably have gotten death would be let go while somebody else who was likely either innocent or undeserving would get death, there was just no way to enforce it in a perfectly fair and error-free way, and all the required appeals cost a huge amount of money and resources. I am reasonably certain we have already executed quite a few innocent people despite all that expenditure.
Prison technology has also evolved. Life without parole (LWOP) these days usually means LWOP, in USA. (Not so much in Europe, where you have situations like the “Monster of Worcester” being let out on parole.)
Therefore, there was no logical reason to support the DP, so I stopped. Fortunately, the Church agrees with my position, so I didn’t have to think too hard about the morality angle.