From 2015–2020, 136 people were executed by state or federal government in the United States. Even if judgments of their guilt were correct, is death an acceptable punishment? The Catholic Church today says no, because their lives were sacred and worthy of a chance for repentance and reconciliation.

Much like the development of other doctrine concerning issues of freedom and life—teachings on slavery and war, for example—the emergence of the Catholic Church’s opposition to the death penalty developed in recent centuries. Generally, before the conversion of the emperor Constantine, Christians were known (and often rebuked) for refusing to participate in the taking of human life for any reason.

Some Christian leaders, such as Lactantius and Pope Nicholas I, opposed use of the death penalty, while others, such as St. Augustine and St. Thomas Aquinas, allowed it when the security of the larger community was at stake. Augustine argued against the widespread use of the death penalty but justified it in cases where the lives of innocent people in the community were at stake. Aquinas justified the death penalty when no other means could protect the common good. Similar theological arguments for the death penalty are found in the writings of Duns Scotus, St. Robert Bellarmine, St. Thomas More, and Francisco Suarez.