Sorry to offend anyone. Modern day Catholic Popes emphasize avoiding the penalty.
In January 1999, Pope John Paul II, without changing Catholic teaching, appealed for a consensus to end the death penalty on the ground that it was “both cruel and unnecessary”. He said that criminal offenders should be offered “an incentive and help to change his or her behavior and be rehabilitated”.
What does the Pope say when the rehabilitation aspect doesn’t work with a convicted criminal? That’s usually when the death penalty has been instituted. It would be preferable when a person doesn’t need to be executed, but there comes a time when execution seems to the only punishment left.