Ed Feser and Joseph Bessette have a book forthcoming from Ignatius Press entitled By Man Shall His Blood Be Shed: A Catholic Defense of the Death Penalty. In an essay at Catholic World Report, they summarize some of the book's key points. The essay is in two parts. The second part will be published later this week. I'll update this post with a link to the second part when it comes out.
Here's how Feser and Bessette formulate one of the claims they defend:
[I]t is the irreformable teaching of the Church that capital punishment can in principle be legitimate, not merely to ensure the physical safety of others when an offender poses an immediate danger (a case where even John Paul II was willing to allow for the death penalty), but even for purposes such as securing retributive justice and deterring serious crime.
To this Feser and Bessette add:
What is open to debate is merely whether recourse to the death penalty is in practice the best option given particular historical and cultural circumstances. That is a “prudential” matter about which popes have no special expertise.
If you are interested in this topic, I recommend Feser and Bessette's essay. I'm sure their forthcoming book will be quite good too.
UPDATE: Here's the link to the second part of Feser and Bessette's essay.