The death penalty in the US works through a slow, tightly regulated sequence: a prosecutor decides to pursue it, a jury selected for its willingness to consider death decides guilt in one phase and sentence in a second, and any death sentence then moves through more than a decade of mandatory appeals before an execution can be carried out. Twenty-seven states and the federal government still authorize capital punishment, but only a handful of states actually execute anyone in a given year, and the Supreme Court has placed several categories of people and crimes entirely off-limits.
Where the Death Penalty Applies
Twenty-seven states authorize capital punishment; 23 states and the District of Columbia have abolished it. Four of the retaining states currently have governor-imposed moratoriums pausing executions: California, Oregon, Pennsylvania, and Ohio. Actual executions are concentrated in a small number of states. In 2025, 47 people were executed across 11 states, up sharply from 25 the year before, driven largely by a surge in Florida.
The federal government runs a separate death penalty for a narrow set of offenses, including certain murders, treason, and espionage.1United States Department of Justice. Capital Eligible Statutes Assigned By Section A federal capital case can produce a death sentence even when the crime occurred in a state that has abolished the practice. A federal execution moratorium in place since July 2021 was lifted by the Department of Justice in February 2025.2United States Department of Justice. Reviving the Federal Death Penalty and Lifting the Moratorium on Federal Executions
The whole system operates under the Eighth Amendment’s ban on “cruel and unusual punishments.”3Legal Information Institute (LII). Eighth Amendment The Supreme Court confirmed in Gregg v. Georgia (1976) that capital punishment is not inherently unconstitutional, so long as state laws give juries meaningful guidance in deciding who receives it.
Who Cannot Be Sentenced to Death or Executed
Even when a state’s statute would seem to allow it, the Supreme Court has drawn categorical lines that no jurisdiction can cross.
Crimes that do not kill the victim generally cannot be punished by death. In Kennedy v. Louisiana (2008), the Court struck down a statute authorizing execution for the rape of a child, holding that “a death sentence for one who raped but did not kill a child, and who did not intend to assist another in killing the child, is unconstitutional.”4Justia U.S. Supreme Court Center. Kennedy v. Louisiana, 554 US 407 (2008) Capital punishment is effectively limited to homicide offenses plus a small number of crimes against the state such as treason and espionage.
Juveniles are exempt. Roper v. Simmons (2005) prohibits executing anyone who was under 18 at the time of the offense.5Justia U.S. Supreme Court Center. Roper v. Simmons, 543 US 551 (2005)
People with intellectual disabilities cannot be executed. Atkins v. Virginia (2002) established the rule.6Legal Information Institute (LII). Atkins v. Virginia Hall v. Florida (2014) later held that states cannot use a rigid IQ score of 70 as the sole cutoff; the assessment has to consider intellectual functioning, adaptive skills, and onset before age 18.7Legal Information Institute (LII). Hall v. Florida (Certiorari Petition Summary)
Finally, a prisoner who is not mentally competent at the time of execution cannot be put to death. Ford v. Wainwright (1986) grounded that ban in the Eighth Amendment.8Justia U.S. Supreme Court Center. Ford v. Wainwright, 477 US 399 (1986) Panetti v. Quarterman (2007) refined the standard: the prisoner must have a rational understanding of the punishment and the reason for it. Reciting the facts of the case is not enough if mental illness prevents genuine comprehension.
The Prosecutor’s Decision to Seek Death
Nothing else happens until a prosecutor decides to pursue a death sentence. Even where a murder clearly qualifies as capital under state law, the local district attorney decides whether to file the notice of intent. That decision is discretionary, is not reviewed by any appellate court, and is not required to be consistent across neighboring counties. Geography, local politics, and the individual prosecutor’s philosophy shape the outcome.
The federal system centralizes this step. Local US Attorneys must submit capital-eligible cases to the Attorney General, who makes the final authorization. That reduces geographic randomness but keeps the decision inside the executive branch.
Death Qualification of the Jury
Capital jury selection includes a step found in no other kind of trial. During voir dire, each prospective juror is questioned individually about their views on the death penalty. A juror whose opposition to capital punishment would prevent or substantially impair the ability to follow the sentencing law can be removed for cause. So can a juror who would automatically vote for death upon any guilty verdict. The Supreme Court upheld this practice, called death qualification, in Lockhart v. McCree.
The goal is a jury that can genuinely consider both possible sentences. In practice, death qualification can take days or weeks. Critics argue the resulting juries skew toward conviction because people who oppose capital punishment tend to be more skeptical of law enforcement generally; supporters respond that a juror who cannot follow the sentencing statute is not impartial.
The Two-Phase Trial
A capital trial is split into two separate phases, and that structure is constitutionally required. The jury first decides guilt without knowing anything about sentencing evidence, and only then, if it has convicted on the capital charge, turns to whether the defendant should live or die.
Guilt Phase
The first phase looks like any serious criminal trial. The prosecution must prove every element of the capital offense beyond a reasonable doubt. If the verdict is not guilty, the case ends. If the jury convicts on a lesser, non-capital charge, no penalty phase happens.
Penalty Phase
A guilty verdict on the capital charge triggers a sentencing hearing that functions almost like a second trial. Both sides call witnesses, introduce exhibits, and make arguments. The rules of evidence are relaxed, especially for the defense, which is allowed to present virtually anything relevant to the argument for a sentence less than death.
Aggravating and Mitigating Factors
The penalty phase turns on two categories of evidence. The prosecution must prove at least one statutory aggravating factor: a circumstance the legislature has defined as making a murder especially deserving of death. Under the federal statute, these include a killing committed during another serious felony such as kidnapping or terrorism, the murder of a law enforcement officer or judge, a prior violent-felony conviction, and a murder committed in a way that involved torture or serious physical abuse.9Office of the Law Revision Counsel. 18 USC 3592 – Mitigating and Aggravating Factors State lists overlap heavily with the federal one.
Mitigating factors are far broader and do not need to be listed in any statute. The jury must consider anything the defendant offers about their character, background, or the circumstances of the offense that argues against execution.9Office of the Law Revision Counsel. 18 USC 3592 – Mitigating and Aggravating Factors Common mitigation includes childhood abuse or neglect, mental illness, cognitive limitations that fall short of the Atkins threshold, addiction, a minor role in the crime, youth, and a lack of prior record. Serious mitigation work usually involves a dedicated defense team that includes a mitigation specialist to reconstruct the defendant’s life history.
The prosecution may also present victim impact evidence: testimony from the victim’s family about who the victim was and how the murder affected them. Payne v. Tennessee (1991) held that the Eighth Amendment does not bar this evidence.10Justia U.S. Supreme Court Center. Payne v. Tennessee, 501 US 808 (1991) Family members still cannot testify about what sentence they think the defendant deserves.
How the Jury Reaches a Sentence
The jury weighs the aggravating and mitigating evidence and makes an individualized decision. Hurst v. Florida (2016) held that the Sixth Amendment requires a jury, not a judge, to find each fact necessary to impose a death sentence, and a judge cannot independently find aggravating factors or override a jury recommendation.
In most death penalty jurisdictions, including the federal system, a non-unanimous jury automatically produces a life sentence without parole. That is not universal. A few states let the prosecution empanel a new jury and try the sentencing phase again after a deadlock. In Indiana and Missouri, a hung jury shifts the sentencing decision to the judge, who can impose death or life. Montana and Nebraska assign the sentencing decision to a judge in every capital case.
Appeals and Post-Conviction Review
Every death sentence triggers a mandatory review process that runs through multiple courts over many years. More than half of current death row prisoners have been awaiting execution for over 18 years. The length is a feature, not a bug: because execution cannot be undone, the system layers on more scrutiny than any other sentence receives.
Direct Appeal
The first stage is automatic. Appellate counsel challenges errors in the trial record: improper jury instructions, wrongly admitted evidence, prosecutorial misconduct during argument, and the like. In most states the appeal goes straight to the state’s highest court, skipping intermediate appellate review. The court looks only at what happened in the courtroom, as reflected in the transcript and exhibits.
State Post-Conviction Review
After direct appeal, the defendant can file a state habeas corpus petition. This stage allows claims that go beyond the trial record. The most common is ineffective assistance of counsel, arguing that the trial lawyer’s performance was so deficient that it undermined the fairness of the proceeding. Other claims include newly discovered evidence, exculpatory material the prosecution withheld, and juror misconduct that only surfaced after trial. Many capital convictions that get overturned fall at this stage, because the flaws were invisible from the record alone.
Federal Habeas Corpus
Once state remedies run out, the defendant can petition a federal court for habeas relief. Federal habeas operates under the Antiterrorism and Effective Death Penalty Act of 1996 (AEDPA), which sets a deliberately high bar. A federal court can grant relief only if the state court’s decision “was contrary to, or involved an unreasonable application of, clearly established Federal law, as determined by the Supreme Court of the United States,” or “was based on an unreasonable determination of the facts.”11Office of the Law Revision Counsel. 28 USC 2254 – State Custody; Remedies in Federal Courts A state court can be wrong without being unreasonably wrong, and the federal court then has to let the conviction stand. Federal habeas is the narrowest of the three review stages and the last chance to raise federal constitutional claims before an execution warrant issues.
Counsel Along the Way
Defendants have a constitutional right to appointed counsel on direct appeal. The right to a lawyer in state or federal habeas proceedings is not constitutionally guaranteed, though many states provide appointed habeas counsel by statute, and federal law funds representation through capital habeas units in states that opt in. The American Bar Association’s guidelines call for a minimum defense team of two qualified attorneys, an investigator, and a mitigation specialist at every stage. Whether a defendant actually gets that level of representation depends heavily on where the case is located and how the local public defense system is funded.
Clemency
After all judicial review is exhausted, clemency is the final safeguard. Every death penalty jurisdiction has some mechanism for the executive branch to commute a death sentence to life imprisonment or grant a reprieve. In some states the governor decides alone. In others, the governor can act only after a recommendation from a clemency board, and in a few states the board itself decides without gubernatorial involvement. For federal death row, the President holds the pardon and commutation power alone. Clemency in capital cases is rare, the decision is discretionary, and courts have little role in reviewing it. Petitions typically point to new evidence of innocence, questions about the fairness of the trial, rehabilitation, or proportionality concerns.
Methods of Execution
Lethal injection is the primary method in every state that still carries out executions and in the federal system. It typically involves intravenous administration of one or more drugs meant to render the prisoner unconscious and stop the heart. Persistent difficulty obtaining the standard drugs has pushed states toward single-drug protocols, compounded drugs from specialty pharmacies, or alternative methods entirely.
Several states authorize backup methods when lethal injection is unavailable or the prisoner chooses an alternative:
- Electrocution remains an authorized alternative in several states, though it is rarely used as a primary method.
- Firing squad, in which a team of volunteer officers fires at a target over the prisoner’s heart, was used in a South Carolina execution in 2025 and is authorized as a backup in a small number of other states.
- Nitrogen hypoxia, in which the prisoner breathes pure nitrogen through a mask until oxygen deprivation causes death, is the newest method. Alabama became the first jurisdiction in the world to use it in January 2024. At least five states now authorize it in some form: Alabama, Louisiana, Mississippi, Oklahoma, and Arkansas.
- Lethal gas, which uses a chemical agent to cause death by oxygen deprivation, remains a statutory option in a few states but has not been widely used in decades.
Hanging has effectively disappeared. The only states that had retained it, New Hampshire and Washington, have both since abolished the death penalty entirely, and no state with an active capital punishment system currently uses hanging.
Time on Death Row and Wrongful Convictions
The mandatory appeals process is the main reason people sentenced to death spend so long awaiting execution. More than half of the current death row population has been there for over 18 years. That length is driven by the review system, not by defendants dragging out the process.
The review system also catches cases that should not have produced a death sentence in the first place. Since 1973, at least 202 people sentenced to death have been exonerated of all charges tied to their capital convictions, through DNA testing, recanted testimony, findings of prosecutorial misconduct, and other post-conviction developments. The average exoneree spent more than a decade on death row before being cleared. Every state has a post-conviction DNA testing statute, though access ranges from broad, deadline-free procedures to narrow windows requiring the defendant to show that identity was contested at trial. Under federal law, a prisoner can seek DNA testing under the Justice for All Act of 2004, but the motion generally must be filed within three years of conviction and the applicant must assert actual innocence under penalty of perjury.