Despite what Jorge Mario Bergoglio AKA [anti-] Pope Francis might say, the Apostles, Church Fathers, Doctors, and Thousands of Years of Tradition all agree that — as the good ol’ Texas saying goes — some folks just need killin’.
But why take my word for it when you could take theirs?
For princes are not a terror to the good work, but to the evil. Wilt thou then not be afraid of the power? Do that which is good: and thou shalt have praise from the same.
For he is God’s minister to thee, for good. But if thou do that which is evil, fear: for he beareth not the sword in vain. For he is God’s minister: an avenger to execute wrath upon him that doth evil. – St. Paul, Romans 13:3-4
For if I have injured them, or have committed any thing worthy of death, I refuse not to die. – St. Paul, Acts 11
You see how he hath furnished him with arms, and set him on guard like a soldier, for a terror to those that commit sin. For he is the minister of God to execute wrath, a revenger upon him that doeth evil. Now lest you should start off at hearing again of punishment, and vengeance, and a sword, he says again that it is God’s law he is carrying out. For what if he does not know it himself? yet it is God that hath so shaped things. If then, whether in punishing, or in honoring, he be a Minister, in avenging virtue’s cause, in driving vice away, as God willeth, why be captious against him, when he is the cause of so many good doings, and paves the way for thine too? since there are many who first practised virtue through the fear of God. – St. John Chrysostom, Homily 23 on Romans
It must be remembered that power was granted by God, and to avenge crime the sword was permitted; he who carries out this vengeance is God’s minister. What motive have we for condemning a practice that all hold to be permitted by God? We uphold, therefore, what has been observed until now, in order not to alter the discipline and so that we may not appear to act contrary to God’s authority. – Pope St. Innocent I
The same divine authority that forbids the killing of a human being establishes certain exceptions, as when God authorizes killing by a general law or when He gives an explicit commission to an individual for a limited time… The agent who executes the killing does not commit homicide; he is an instrument as is the sword with which he cuts. Therefore, it is in no way contrary to the commandment, ‘Thou shalt not kill’ to wage war at God’s bidding, or for the representatives of public authority to put criminals to death, according to the law, that is, the will of the most just reason. – St. Augustine, The City of God
Therefore if a man be dangerous and infectious to the community, on account of some sin, it is praiseworthy and advantageous that he be killed in order to safeguard the common good. – St. Thomas Aquinas, Summa Theologiae
It is permissible to kill a criminal if this is necessary for the welfare of the whole community. However, this right belongs only to the one entrusted with the care of the whole community — just as a doctor may cut off an infected limb, since he has been entrusted with the care of the health of the whole body. – St. Thomas Aquinas, Summa Theologiae
The fact that the evil ones, as long as they live, can be corrected from their errors does not prohibit that they may be justly executed, for the danger which threatens from their way of life is greater and more certain than the good which may be expected from their improvement… They also have at that critical point of death the opportunity to be converted to God through repentance. And if they are so obstinate that even at the point of death their heart does not draw back from malice, it is possible to make a quite probable judgment that they would never come away from evil. – St. Thomas Aquinas, Summa Contra Gentiles