Item — “Pope Francis: Death penalty is a ‘mortal sin’”
This means, in the pontiff’s opinion (see below), that anyone — a judge, the prison guards, the person administering the lethal drugs, and others — involved in sentencing of someone to death, upholding such a sentencing, or participating in the execution, even peripherally, is in a state of grave sin which would condemn them to hell should they die without asking and obtaining God’s forgiveness. It also means, if they are Catholic, that they cannot receive Holy Communion at Mass until they receive absolution at Confession for their mortal sin(s).
Q. 1276. Under what circumstances may human life be lawfully taken?
A. Human life may be lawfully taken:
1. In self-defense, when we are unjustly attacked and have no other means of saving our own lives;
2. In a just war, when the safety or rights of the nation require it;
3. By the lawful execution of a criminal, fairly tried and found guilty of a crime punishable by death when the preservation of law and order and the good of the community require such execution.
Item 1 relates to personal self-defense, Item 2 to national self-defense, and Item 3 to societal self-defense.
If you weaken Point 3, you potentially weaken Points 1 and 2; evil would like nothing better.
If society isn’t allowed to defend itself from incorrigible murderers and to create a culture which deters others who might turn into incorrigible murderers, then neither can nations or individuals. Game over. Evil wins.
The Pope cannot repeal Church doctrine as explained above without issuing a formal encyclical. Prediction: He won’t do it.
Until an encyclical appears, the death penalty, administered consistent with Point 3, remains operative, and Pope Francis’s opinion is irrelevant to Catholics with properly formed consciences who are practicing their faith.