The blood-dancing nun believes the death penalty is always wrong.
The press identify Prejean in a way that would make her seem a legitimate spokesperson for the official teaching of the Roman Catholic Church. She is rather a one-nun show than a Vatican envoy. She has run her anti-death-penalty lobby business sisterjean.org since 2004 (and in other forms before her internet presence).
Using her position as a Catholic woman religious for political traction is one of the things meant in the commandment about taking God's name in vain.
If nothing else, she continues to insult the unborn and other innocents whose lives are taken, when she conflates abortion / war / self-defense / death-penalty.
Here's a thought: Jesus Christ suffered under Pontius Pilate and was crucified. He spoke from the cross. One of the things He did NOT say was, "Oh, and by the way, this thing they are doing here? This death-penalty thing? It's always wrong."
I think honest people come to the conclusion that war, the death penalty, and the use of lethal force in self-defense are sometimes the PRO-LIFE thing to do.
UPDATE: Appeals court had struck down the death penalty for Tsarnaev. The Supreme Court reinstated the death penalty for the 2013 murders in March of 2022.