-Pope Pius XII
"Assuming that the guilty party's identity and responsibility have been fully determined, the traditional teaching of the Church does not exclude recourse to the death penalty if this is the only possible way of effectively defending human lives against the unjust aggressor. If, however, non-lethal means are sufficient to defend and protect people's safety from the aggressor, authority will limit itself to such means, as these are more in keeping with the concrete conditions of the common good and more in conformity to the dignity of the human person"
-Pope John Paul II
"Today the death penalty is inadmissible, no matter how serious the crime committed."
Until Pope Francis, the Church had been pretty clear that they were willing to allow diversity of opinion within the flock on capital punishment. It is, IMO, a hypocritical view to maintain in any organization or individual that professes to be "pro-life". Capital punishment is essentially a form of playing God.
Personally, I think a death sentence is justified in some rare circumstances, but I also don't consider myself pro-life, nor am I a believer. Therefore, my views are consistent.