The United States has the death penalty because the Supreme Court has repeatedly held that executions do not automatically violate the Constitution when carried out under strict procedures, and because supporters continue to defend capital punishment on three main grounds: that some crimes deserve the harshest possible response, that the threat of execution may deter others, and that an executed offender can never kill again. Why do we have the death penalty in the first place is a question that pulls together constitutional law, moral philosophy, and practical policy, and the answer looks different depending on which strand you pick up first. Twenty-seven states, the federal government, and the U.S. military currently authorize capital punishment for certain crimes.1National Conference of State Legislatures. States and Capital Punishment
Retribution: The Oldest Reason
The most straightforward argument for the death penalty is retribution. Some crimes are so devastating, the argument goes, that only the most severe sentence available reflects their actual gravity. This is not revenge in a personal sense. It is a philosophical claim that the legal system loses credibility if its worst response cannot match the worst acts a person can commit. Sentencing a mass murderer to the same prison term as someone convicted of a single killing, proponents argue, fails to acknowledge the difference between those crimes in any meaningful way.
Retribution treats punishment as something an offender has earned rather than as a tool to achieve a future outcome. The focus is backward-looking: what did this person do, and what do they deserve for having done it? For supporters, capital punishment exists because certain acts cross a threshold where no lesser sentence adequately represents society’s condemnation. Critics argue the state should not be in the business of calibrating suffering, but the retributive case remains the most emotionally resonant one and the argument jurors are most likely to hear during a sentencing hearing.
Deterrence: Intuitive but Hard to Prove
Deterrence is the argument you hear most often in political debate. If potential murderers know they face execution, they will think twice. It sounds like common sense, and supporters have pointed to studies claiming that each execution prevents a measurable number of future homicides. The empirical foundation is thinner than the rhetoric suggests.
The most authoritative review came from the National Research Council in 2012, which examined three decades of deterrence research and concluded that none of it was reliable enough to answer whether the death penalty increases, decreases, or has no effect on murder rates. The panel found that existing studies failed to account for the deterrent effect of non-capital punishments, relied on implausible models of how potential murderers perceive risk, and produced unstable results. With minor adjustments to the same datasets, estimates ranged from 429 lives saved per execution to 86 additional lives lost. A separate survey of criminologists found that 88% did not believe the death penalty had been shown to deter homicide.
None of this proves the death penalty does not deter anyone. It means that after decades of study, researchers cannot demonstrate that it does. The deterrence rationale persists in public discourse largely because it feels obvious.
Incapacitation: The Practical Argument
The most pragmatic reason given for capital punishment is permanent incapacitation. An executed offender will never kill again. Unlike deterrence, this claim does not depend on what other people might do. It focuses on the individual defendant and the certainty that execution removes any future risk they pose to the public, prison staff, or other inmates.
Future dangerousness is explicitly built into sentencing in several jurisdictions. Texas requires a jury to decide whether the defendant would likely commit violent acts in the future before imposing death. At the federal level, the sentencing hearing under 18 U.S.C. § 3593 considers the defendant’s history of violence and risk of recidivism.2Office of the Law Revision Counsel. 18 U.S.C. 3591 – Sentence of Death The counterargument is that life without parole achieves the same outcome in practice, since an offender held in a maximum-security facility until they die of natural causes poses negligible risk to the public. Proponents respond that life sentences still carry the theoretical possibility of escape, clemency, or violence inside the prison.
Why the Courts Have Not Ended It
The Eighth Amendment prohibits “cruel and unusual punishments.”3Congress.gov. U.S. Constitution – Eighth Amendment Whether the death penalty falls inside that prohibition has been litigated for decades, and the Supreme Court’s answer has shifted. In 1958, Trop v. Dulles established that the Eighth Amendment “must draw its meaning from the evolving standards of decency that mark the progress of a maturing society,” framing the constitutionality of any punishment as a moving target rather than a fixed rule.4Justia Law. Trop v Dulles, 356 U.S. 86 (1958)
In 1972, Furman v. Georgia struck down every existing death penalty statute in the country. The Court found that the way states were applying capital punishment was so arbitrary that it violated the Eighth Amendment, pointing to the “uncontrolled discretion of judges or juries” that left defendants living or dying based on what the Court called “the whim of one man or of 12.”5Justia Law. Furman v Georgia, 408 U.S. 238 (1972) Every death sentence in America was voided overnight.
The moratorium lasted four years. States rewrote their capital statutes with tighter procedures, and in 1976, the Court upheld Georgia’s new law in Gregg v. Georgia. The key requirement was a bifurcated process: a guilt phase followed by a separate sentencing phase in which the jury weighs specific aggravating and mitigating factors before deciding whether death is warranted. The Court held that this structure, combined with automatic appellate review, addressed the arbitrariness problem from Furman.6Justia Law. Gregg v Georgia, 428 U.S. 153 (1976) Executions resumed. The basic template from Gregg still governs every capital case today, which is the reason the courts have not simply ended the practice: once procedural safeguards exist, the Supreme Court has treated the sentence itself as constitutional.
Where the Death Penalty Actually Applies
Twenty-three states have abolished capital punishment, with Virginia, Colorado, and Washington among the most recent to repeal. Four more states that technically authorize it maintain gubernatorial moratoriums: California (since 2019), Oregon (continuing a 2011 hold, with all existing death sentences commuted in 2022), Pennsylvania, and Ohio, whose governor said in early 2025 that he does not anticipate any further executions during his term.
The federal death penalty runs on a separate track. It applies across all 50 states and U.S. territories, which means the federal government can seek execution for qualifying crimes even in states that have abolished it. Sixteen federal executions have been carried out in the modern era, with 13 occurring in a concentrated six-month period between July 2020 and January 2021. President Biden later imposed a moratorium on federal executions and commuted 37 federal death sentences in December 2024.7Death Penalty Information Center. Federal Death Penalty In January 2025, President Trump signed an executive order directing the Attorney General to “pursue the death penalty for all crimes of a severity demanding its use” and to help states obtain drugs needed for lethal injection.8The White House. Restoring The Death Penalty And Protecting Public Safety
What the Law Excludes
Even where the death penalty exists, the Supreme Court has carved out categorical limits on who can be executed and for what. These exclusions matter because they define the actual reach of a punishment that in popular discussion often sounds broader than it is.
In 2002, Atkins v. Virginia held that executing a person with an intellectual disability violates the Eighth Amendment.9Justia Law. Atkins v Virginia, 536 U.S. 304 (2002) Three years later, Roper v. Simmons barred execution of anyone who was under 18 when they committed the crime.10Justia Law. Roper v Simmons, 543 U.S. 551 (2005) And in 2008, Kennedy v. Louisiana ruled that the Eighth Amendment prohibits execution for crimes against individuals that do not result in the victim’s death, holding that capital punishment must be “reserved for the worst of crimes.”11Legal Information Institute. Kennedy v Louisiana Treason and espionage remain death-eligible because they are classified as offenses against the state rather than against an individual victim.12Office of the Law Revision Counsel. 18 U.S.C. 2381 – Treason
At the federal level, a conviction alone is never enough. Under 18 U.S.C. § 3591, death is available only when the defendant intentionally killed someone, caused a death through serious bodily injury, or participated in violence with reckless disregard for human life that resulted in death.2Office of the Law Revision Counsel. 18 U.S.C. 3591 – Sentence of Death The prosecution must then prove at least one statutory aggravating factor during the penalty phase before the jury can even consider a death sentence.13Office of the Law Revision Counsel. 18 U.S.C. 3592 – Mitigating and Aggravating Factors
The Arguments Pushing the Other Way
No account of why the United States still has the death penalty is complete without the arguments that have steadily eroded its reach. These do not refute the retributive, deterrence, or incapacitation cases on their own terms, but they explain why abolition keeps gaining ground.
It Costs More Than Life in Prison
One of the least intuitive facts about the death penalty is that it costs far more than keeping someone in prison for life. Most people assume that decades of incarceration must be more expensive than a single execution. The opposite is true, and the gap is not small.
Capital defendants are entitled to two court-appointed attorneys. Jury selection takes dramatically longer because prospective jurors must be individually questioned about their willingness to impose death. Capital trials run roughly four times longer than comparable non-capital trials. Both sides retain expert witnesses in forensic evidence, mental health, and the defendant’s background. After conviction, every death-sentenced prisoner is entitled to a series of appeals at taxpayer expense, a process that routinely spans a decade or more. Death row housing itself is more expensive, typically involving specialized solitary units with enhanced security. A Kansas audit found the median cost of a death penalty case through execution was $1.26 million, compared to $740,000 for a comparable non-capital case. Trial costs alone were roughly 16 times higher in capital cases.
Wrongful Convictions
Since 1973, at least 202 people sentenced to death in the United States have been fully exonerated of all charges related to their wrongful convictions. That number represents people who came close to being executed for crimes they did not commit, and it raises an uncomfortable question about any irreversible punishment: how many innocent people were not caught in time?
Official misconduct by police or prosecutors has been identified in more than half of known wrongful convictions, including concealment of evidence favorable to the defendant and coercion of witnesses. Eyewitness misidentification appears in roughly 28% of exonerations. False confessions account for about 12%, with young people and those with intellectual disabilities particularly vulnerable to coercive interrogation. Supporters argue the exoneration numbers show the system working, catching mistakes before execution. Critics respond that 202 exonerations over five decades represent only the errors that were discovered.
Public Support Is Declining
American support for the death penalty has been falling for decades. Gallup polling from October 2025 found that 52% of Americans favor capital punishment, the lowest level in 50 years, while 44% oppose it, the highest opposition recorded since 1966. In the mid-1990s, support regularly exceeded 75%. The shift reflects a broader reckoning with cost, the risk of executing innocent people, racial disparities in sentencing, and the availability of life without parole as an alternative that satisfies the incapacitation goal without the finality of death.