Does the death penalty deter crime?

 

CNA Staff, Feb 10, 2025 / 06:00 am (CNA).

On his first day in office, President Donald Trump signed an executive order promoting the death penalty as an “essential tool for deterring and punishing those who would commit the most heinous crimes and acts of lethal violence against American citizens.”

Following through on copious rhetoric from Trump on the campaign trail, the Jan. 20 order aims to overturn Supreme Court precedents limiting capital punishment, increase its use in federal cases, and ensure states have sufficient lethal injection drugs.

The question of whether the use of the death penalty actually deters and lowers rates of crime — as Trump presumes in his order — is a long-simmering one, with both proponents and opponents of the death penalty variously claiming evidence in their favor.

Here’s a look at the issue.

What does the evidence say?

From a social science perspective, the evidence for whether the death penalty actually deters crime is highly disputed.

Robin Maher, executive director of the Washington D.C.-based nonprofit Death Penalty Information Center (DPIC), told CNA that studies they have reviewed “consistently fail” to demonstrate a link between capital punishment and reduced crime.

She pointed to a resource page from the DPIC that summarizes a number of studies on the death penalty’s deterrent effect. Chief among them is a 2012 study from the congressionally-chartered National Research Council (NRC), which concluded that the existing research was “not informative about whether capital punishment decreases, increases, or has no effect on homicide rates,” while cautioning that “lack of evidence is not evidence for or against the hypothesis.”

A more recent study from 2023, controlling for a number of variables, found that states that placed a moratorium on the death penalty in recent years actually saw a very slight decrease in homicide rates, suggesting the presence of the death penalty had a very small or even nonexistent deterrent effect.

Meanwhile, some studies purporting to demonstrate a strong deterrent effect of the death penalty — some even going so far as to hypothesize how many innocent lives an execution can reasonably be expected to save — have been criticized for apparent shortcomings in accounting for other factors that influence homicide rates.

For her part, Maher said the idea that the death penalty is an especially effective deterrent of crime ignores the fact that a significant number of offenders suffer from severe mental illness or trauma. The actions of such people are less likely to be driven by rational cost-benefit analyses than a healthy person’s actions, she said.

“For someone who doesn’t have these impediments to deal with, who can think about the consequences of committing a crime very rationally and logically, those folks might make a different decision if there’s a death sentence as a possible consequence. But the reality is most murders are committed by people who have serious impairments, physical or mental,” she explained.

While it may be true that the death penalty has some deterrent effect, the DPIC’s resource page notes that other pun­ish­ments, such as life in prison with­out parole, might pro­vide equal deter­rence at far less cost, and with­out the atten­dant risk of exe­cut­ing an inno­cent per­son.

Additionally, the aforementioned 2023 study opines that “increased certainty of sanctions” — in other words, offenders’ perception of how likely the threat of punishment is if they break the law — may be a more effective deterrent than “a policy permitting a more severe punishment.”

“All punishment has a specific deterrent effect of some kind already. The fact that you are putting someone in a prison environment, often for the rest of their natural life, is also a very significant punishment that should, in theory, deter future crime,” Maher said.

What should Catholics make of this?

The question of whether or not the death penalty deters crime has not been central to the teachings of recent popes on the death penalty. The writings of St. John Paul II, Benedict XVI, and Francis have instead emphasized the inherent dignity of all human beings, even those who have committed crimes.

The Catechism of the Catholic Church, reflecting a 2018 update promulgated by Pope Francis, describes the death penalty as “inadmissible” and an “attack on the inviolability and dignity of the person” (No. 2267). Because of this teaching, the Church “works with determination for its abolition worldwide,” the catechism continues.

Most recently, Pope Francis underlined his strong opposition to capital punishment in a book preface, saying that “the death penalty is in no way a solution to the violence that can strike innocent people.”

“Capital executions, far from bringing justice, fuel a sense of revenge that becomes a dangerous poison for the body of our civil societies,” the pope said.

That said, Catholics in the U.S. public sphere, including the U.S. bishops, have occasionally made reference to the “deterrence” argument for the death penalty in recent decades.

In a 1980 statement on the death penalty, the U.S. Conference of Catholic Bishops (USCCB) noted that “while it is certain that capital punishment prevents the individual from committing further crimes, it is far from certain that it actually prevents others from doing so.”

“There are strong reasons to doubt that many crimes of violence are undertaken in a spirit of rational calculation which would be influenced by a remote threat of death. The small number of death sentences in relation to the number of murders also makes it seem highly unlikely that the threat will be carried out and so undercuts the effectiveness of the deterrent,” the bishops wrote.

Further, the bishops noted the practical reality that lengthy delays in carrying out executions “diminishes the effectiveness of capital punishment as a deterrent, for it makes the death penalty uncertain and remote. Death row can be the scene of conversion and spiritual growth, but it also produces aimlessness, fear, and despair.”

Krisanne Vaillancourt Murphy, executive director of the anti-death penalty group Catholic Mobilizing Network (CMN), directly criticized the deterrence argument contained in Trump’s Jan. 20 order.

“​​What we know about the death penalty is that it does not deter crime or make communities safer. It’s immoral, flawed, and risky; arbitrary and unfair; cruel and dehumanizing. Both the state and federal death penalty systems are broken beyond repair and emblematic of a throwaway culture,” Vaillancourt Murphy said in a statement to CNA at the time.

Taking a different view, Edward Feser, a Catholic philosopher who coauthored a 2017 book defending the use of the death penalty, told CNA that while not the main focus of its argument, he believes social science favors the idea that the death penalty does deter crime.

In the book “By Man Shall His Blood Be Shed,” Feser and his coauthor Joseph Bessette cite nine peer-reviewed studies that purport to demonstrate a deterrent effect while also tipping a hat to the aforementioned NRC study that equivocated on the question.

The “inconclusiveness” of the statistical evidence, they assert — echoing the U.S. bishops’ 1980 statement — “can plausibly be attributed to such factors as protracted appeals processes and other obstacles to carrying out executions, which dilute the deterrent effects of the death penalty,” adding “for which opponents of capital punishment are themselves largely responsible.”

While concluding in the book that “from the perspective of quantitative social science, the deterrent effect of the death penalty is very much an open question,” Feser argued to CNA that it is “silly to suppose in the first place that this is the sort of thing one really needs social scientific studies to establish.”

“Nobody thinks that any sort of punishment will always deter everyone everywhere. But nobody doubts that punishments will at least deter many people much of the time, and that harsher punishments will, all things being equal, have a greater deterrence effect. It quite obviously follows that the death penalty is bound to have deterrence value,” he said.

In the book, Feser and Bessette argue that the Catholic Church has historically affirmed the legitimacy of capital punishment as a just practice. They acknowledge that there have always been different views within the Church on the application of the death penalty but maintain that the Church’s teaching that capital punishment is legitimate in principle has been consistent.

Addressing concerns raised by others that the death penalty has been applied fallibly and in a biased manner in the United States, Feser said the solution ought “not be to get rid of it but rather to reform it so that it is applied in a fair way.”

“[G]iven that the death penalty deters, mercy toward the innocent would require making use of it. But there is also a kind of mercy to the guilty person himself, if we are looking at things from a theological point of view and not just from a worldly point of view. For this life is, of course, not what is most important. What is most important is the destiny of one’s soul in the next life,” he said.

“St. Thomas Aquinas pointed out that the prospect of execution can actually prod an offender to repent of his evildoing while he still has time to get himself right with God. And as the catechism teaches, when an offender accepts a deserved punishment in a penitential spirit, it has expiatory value. It contributes to the salvation of his soul.”