Does the death penalty deter crime? Decades of research say no. The most authoritative review of the evidence, a 2012 report by the National Research Council, found the studies too flawed to support any claim of a deterrent effect, and states that carry out executions consistently report higher homicide rates than those that don’t.1National Institute of Justice. Deterrence and the Death Penalty
What the Research Actually Shows
The National Research Council, operating under the National Academies of Sciences, published its landmark report in 2012 after reviewing three decades of deterrence research conducted since capital punishment resumed in the United States. The committee’s conclusion was blunt: the studies to date were “not useful in determining the deterrent effect of the death penalty on homicide rates” because none had adequately accounted for the effect of alternative punishments like life without parole.1National Institute of Justice. Deterrence and the Death Penalty Even studies claiming to show deterrence couldn’t separate the effect of the death penalty from the effect of simply locking someone up forever.
That finding didn’t surprise the people who study crime for a living. A survey of leading criminologists found that 88% did not believe the death penalty is a proven deterrent, and 87% said abolishing it would have no significant effect on murder rates.2Death Penalty Information Center. Studies on Deterrence, Debunked The few studies that did claim a deterrent effect relied on statistical models so sensitive that small changes in assumptions could flip the results entirely. The National Research Council flagged this instability as a fundamental problem. If a study’s conclusion changes based on which years you include or how you define a control group, the conclusion doesn’t hold much weight.
Homicide Rates With and Without the Death Penalty
If the death penalty worked as a deterrent, states that use it would have lower murder rates than those that don’t. The opposite is true. Over a twenty-year tracking period, homicide rates in death penalty states ran 48% to 101% higher than in states without capital punishment.3Death Penalty Information Center. Murder Rate of Death Penalty States Compared to Non-Death Penalty States The gap has widened since 1990, not narrowed.
The regional breakdown is even more striking. The South accounts for roughly 82% of all executions carried out in the United States since 1977 yet consistently maintains the highest regional murder rate.4Death Penalty Information Center. The Geographic Arbitrariness of Capital Punishment in the United States The Northeast, which has carried out just four executions since 1976, maintains the lowest murder rate.5Death Penalty Information Center. Murder Rate Declines in Every Region Except the South, Where Executions Are Most Prevalent If executions deterred killing, the South should be the safest region in the country. It isn’t close.
States that have repealed the death penalty reinforce the pattern. Virginia, Colorado, New Hampshire, Maryland, Connecticut, Illinois, and New Mexico all abolished capital punishment between 2009 and 2021, and none experienced the surge in violent crime that abolition opponents predicted. Their homicide rates continued to track the same national trends as states that kept the death penalty on the books.
Why Deterrence Theory Breaks Down in Practice
The theoretical case for the death penalty as a deterrent rests on what criminologists call the rational choice model. A person considering a murder weighs the potential gain against the risk of punishment, and the threat of execution tips the scale away from the crime. For that logic to work, three conditions have to be met. The punishment must be certain, swift, and severe. The death penalty scores high on severity but fails the other two so thoroughly that severity alone can’t carry the load.
Start with certainty. In 2023, courts imposed just 15 new death sentences nationwide.6Bureau of Justice Statistics. Capital Punishment, 2023 – Statistical Tables With roughly 20,000 homicides that year, the odds of receiving a death sentence were vanishingly small. Whether a killer faces execution depends far more on geography, the quality of their lawyer, and the local prosecutor’s preferences than on the severity of the crime itself. That randomness is the opposite of certainty.
Speed is equally absent. For the prisoners executed in 2019, the average gap between sentencing and execution was 22 years.7Death Penalty Information Center. Bureau of Justice Statistics Reports Number on Death Row Down, Average Time on Death Row Approaches 19 Years A punishment carried out two decades after the crime bears no psychological resemblance to an immediate consequence. And most people sentenced to death are never executed at all. Their sentences get overturned on appeal, commuted, or outlast the defendant through natural death.
That last point is where life without parole becomes the critical comparison. If a would-be killer faces either dying in prison after decades of appeals or simply spending the rest of their life in prison, the practical difference in deterrent effect is hard to identify. The National Research Council specifically criticized existing studies for failing to measure whether the death penalty deters crime any more than life without parole does.1National Institute of Justice. Deterrence and the Death Penalty Until that question is answered, claims of unique deterrence from capital punishment remain unsupported.
Could Executions Actually Increase Homicides?
A competing theory argues that executions don’t just fail to deter homicide but may actually increase it. Known as the brutalization effect, this hypothesis holds that when the state kills someone as a legal remedy, it sends an unintended signal that lethal violence is an acceptable response to wrongdoing. The mechanism resembles what researchers observe after other high-profile violent events, including publicized suicides and mass shootings: a temporary spike in similar behavior follows the event’s visibility.
The earliest and most cited evidence comes from an analysis of monthly homicide data in New York State from 1907 to 1963, which found an average of two additional homicides in the month following an execution. More recent data from California is mixed. In the four months after the state’s first execution in 25 years (Robert Alton Harris in 1992), the average monthly homicide count rose from 306 to 333. After a second execution the following year, the average declined slightly.
The brutalization effect remains contested, and the data is messier than either side would prefer. What is clear is that the evidence cuts against the idea that executions send a simple deterrent message to the public.
Where Things Stand Now
The use of capital punishment in the United States has been declining for years. Twenty-seven states still authorize the death penalty, but many rarely or never carry out executions. The 15 new death sentences imposed in 2023 are a fraction of the numbers seen in the 1990s.6Bureau of Justice Statistics. Capital Punishment, 2023 – Statistical Tables Around 2,100 people remain on state death rows nationwide, and the federal death row has shrunk to three prisoners after President Biden commuted 37 federal death sentences in 2024.8Death Penalty Information Center. Department of Justice Releases Memo Calling for Expansion of Federal Death Penalty and New Methods
Public support has followed a similar trajectory. An October 2025 Gallup poll found that 52% of Americans favor the death penalty for murder, a five-decade low. When respondents are offered life without parole as a specific alternative, support drops further — a previous Gallup poll found 60% preferred the life sentence option.
Federal policy is moving the other direction. In February 2025, the Department of Justice lifted the federal execution moratorium that had been in place since 2021. In April 2026, the DOJ directed the Bureau of Prisons to reinstate lethal injection protocols and expand execution methods to include firing squad, electrocution, and lethal gas, and directed federal prosecutors to seek the death penalty in all cases deemed appropriate.8Death Penalty Information Center. Department of Justice Releases Memo Calling for Expansion of Federal Death Penalty and New Methods No federal prisoner has been executed since 2021, and the legal challenges ahead are substantial.
The underlying question has an answer the data keeps reinforcing. Capital punishment may serve retributive or political purposes, but three decades of research have failed to show it makes anyone safer. The places that use it most have the most homicides, the experts who study it overwhelmingly reject its deterrent value, and the system that administers it is too slow, too rare, and too arbitrary to function as the rational disincentive its supporters describe.