Death Penalty Sanctions: Eligible Crimes, Trial, and Appeals

In the United States, the death penalty applies to a narrow set of crimes and process requirements: murder with a specific aggravating factor in states that still authorize capital punishment, plus a short list of federal offenses that include treason, espionage, certain homicides, and the most serious drug-kingpin crimes. Beyond the qualifying charge, imposing a death sentence requires a separate sentencing hearing, a jury finding of at least one aggravating circumstance beyond a reasonable doubt, and a unanimous vote after the defense presents mitigating evidence. Twenty-seven states authorize capital punishment; twenty-three have abolished it.

Which Crimes Qualify

At the state level, first-degree murder is the primary capital offense. Most states require proof that the killing was premeditated or committed with specific intent. Many states also treat felony murder as capital when a death occurs during a dangerous underlying crime like robbery, kidnapping, or arson. The Supreme Court has narrowed this: a defendant who did not personally kill can be sentenced to death only if they were a major participant in the felony and showed reckless indifference to human life.¹ A minor player with no intent to kill, such as a getaway driver, cannot constitutionally be sentenced to death.

Federal law authorizes the death penalty under 18 U.S.C. § 3591 for a limited set of offenses. Treason and espionage stand on their own because of the national-security harm they cause. For every other capital-eligible federal offense, the government must prove a link to death: that the defendant intentionally killed, inflicted injury that caused death, participated in an act expecting lethal force would be used and someone died, or engaged in violence with reckless disregard for human life that directly caused a death.²

Large-scale drug trafficking is also capital-eligible federally, but only in narrow circumstances. The defendant must have run a continuing criminal enterprise involving at least twice the quantity of controlled substances or twice the gross receipts set by statute, or must have been a top leader who ordered or assisted an attempt to kill a witness, juror, or public official to obstruct the investigation.²

A hard constitutional line runs beneath all of this. In Kennedy v. Louisiana (2008), the Supreme Court held that the Eighth Amendment prohibits the death penalty for crimes against individuals that do not result in death, even crimes as severe as child rape.³ Capital punishment for crimes against individuals is reserved for those who take the victim’s life. The only non-homicide offenses that still qualify are crimes against the state itself, like treason and espionage.

Where the Death Penalty Can Be Imposed

Twenty-seven states currently authorize capital punishment. Some of those states operate under a governor-ordered moratorium that halts executions without repealing the statute; death sentences can sometimes still be imposed, but executions do not go forward while the moratorium is in place.

The federal government runs its own capital system independent of the states. One consequence catches people off guard: federal prosecutors can pursue a death sentence for a federal crime committed inside a state that has abolished capital punishment. The U.S. military also has separate capital authority under the Uniform Code of Military Justice, which allows general courts-martial to impose the death penalty for offenses the code specifically authorizes.⁴

Aggravating Circumstances the Prosecution Must Prove

A conviction for a capital-eligible crime is not enough on its own. The prosecution must prove at least one specific aggravating circumstance beyond the basic elements of the offense. If the jury finds no aggravating factor, the court must impose a sentence other than death.⁵

Federal aggravating factors for homicide offenses include murder of a law enforcement officer, judge, or corrections employee performing their duties; murder for hire or financial gain; and intentionally killing or attempting to kill more than one person in a single criminal episode.⁶ For treason and espionage, the aggravating factors focus on whether the defendant created a grave risk to national security or a grave risk of death, or had a prior conviction for espionage or treason. State statutes define their own lists, which overlap with the federal set but vary in the specifics.

A jury, not a judge, must find these aggravating facts. In Ring v. Arizona (2002), the Supreme Court ruled that any fact exposing a defendant to a greater punishment than the guilty verdict alone would support must be found by a jury beyond a reasonable doubt.⁷ The Court reinforced that principle in Hurst v. Florida (2016), striking down Florida’s system that let judges make the critical death-penalty findings and holding that an advisory jury recommendation was not enough.⁸

The Two-Phase Trial and Mitigating Evidence

Capital cases are tried in two separate phases. The first phase determines guilt or innocence. If the jury convicts of a capital offense, a second hearing decides between death and life imprisonment. Under federal law, the sentencing hearing goes to the same jury that returned the guilty verdict; if the defendant pleaded guilty or the original jury was discharged, a new twelve-member jury is impaneled for sentencing.⁵

The defense presents mitigating factors during this hearing. In Lockett v. Ohio (1978), the Supreme Court established that a defendant must be allowed to present virtually any evidence about their character, background, or the circumstances of the offense as a reason for a lesser sentence.⁹ Because death is qualitatively different from every other punishment, each defendant is entitled to an individualized assessment.

Federal law lists specific mitigating factors the jury must consider:

Impaired capacity to understand the wrongfulness of the conduct or to conform to the law.
Duress, meaning the defendant acted under unusual and substantial pressure.
Minor participation in a crime committed by someone else.
No significant prior criminal history.
Severe mental or emotional disturbance at the time of the offense.
Equally culpable co-defendants who will not receive the death penalty.

The statute also includes a catch-all provision letting the jury weigh any other aspect of the defendant’s life or the circumstances of the offense.⁶ This is where defense teams introduce childhood abuse, mental illness, military service, or other personal history. The jury then weighs the aggravating factors against the mitigating factors, and a death sentence requires a unanimous vote. If even one juror dissents, the sentence drops to life imprisonment or a lesser term.⁵

Who Cannot Be Executed

Regardless of the crime, the Supreme Court has placed several groups of defendants beyond the reach of capital punishment. These limits turn on who the defendant is, not what they did.

Juveniles

No one who was under 18 at the time of the offense can be sentenced to death. In Roper v. Simmons (2005), the Court pointed to three characteristics that make juveniles less culpable than adults: a lack of maturity that leads to impulsive decisions, vulnerability to negative influences and peer pressure, and a character that is still forming.¹⁰ Federal law codifies this restriction directly in the sentencing statute.²

Intellectual Disability

People with intellectual disabilities are categorically exempt. The Supreme Court reached that conclusion in Atkins v. Virginia (2002), finding that a national consensus had developed against executing intellectually disabled individuals and that the practice violated evolving standards of decency under the Eighth Amendment.¹¹ The Court left states to develop their own standards for making that determination, which has produced ongoing litigation over IQ cutoffs and diagnostic criteria.

Mental Incompetence at the Time of Execution

Even after a valid death sentence, the Eighth Amendment prohibits executing someone who has become mentally incompetent. The standard, set in Ford v. Wainwright (1986), bars execution of a prisoner who does not understand the punishment they are about to receive or why.¹² The Court clarified in Panetti v. Quarterman (2007) that bare factual awareness is not enough; a prisoner must have a rational understanding of the connection between the crime and the execution.¹³ In Madison v. Alabama (2019), the Court extended that framework to dementia and memory loss: a prisoner who cannot remember the crime may still be competent if they otherwise understand the punishment, but when a mental condition eliminates the ability to comprehend why the state is executing them, the Eighth Amendment bars going forward.¹⁴

Methods of Execution

Lethal injection is the primary method used by the federal government and every state that authorizes capital punishment.¹⁵ Most states designate a secondary method that becomes available if lethal-injection drugs cannot be obtained or the method is held unconstitutional. Those backup methods vary by jurisdiction and include electrocution, nitrogen hypoxia, lethal gas, and firing squad. Each is governed by a detailed administrative protocol that varies from state to state.

Appeals After a Death Sentence

A death sentence triggers one of the longest appellate processes in the American legal system. Capital cases often spend years or decades on review, and deadlines are strict.

Direct Appeal and State Post-Conviction Review

After sentencing, the defendant has a right to a direct appeal to the state’s highest court, or in federal cases to the applicable federal appellate court. This appeal challenges errors that occurred during the trial or sentencing hearing. If it fails, the defendant can file a state post-conviction petition raising claims outside the trial record, such as ineffective assistance of counsel or newly discovered evidence. State-level proceedings generally have to be completed before federal review is available.

Federal Habeas Corpus

Once state remedies are exhausted, a capital defendant can file a federal habeas corpus petition challenging the constitutional validity of the conviction or sentence. The Antiterrorism and Effective Death Penalty Act of 1996 (AEDPA) imposes a one-year filing deadline, which generally starts when the state conviction becomes final after direct appeal.¹⁶ Time spent on a properly filed state post-conviction petition does not count against that clock.

AEDPA also raised the substantive bar. A federal court can overturn a state court’s decision only if it was contrary to clearly established Supreme Court precedent or based on an unreasonable reading of the facts. A second habeas petition faces even tighter restrictions and requires approval from a federal appellate court.¹⁶

Executive Clemency

The last avenue is clemency. For federal death sentences, the defendant applies to the President through the Department of Justice’s Office of the Pardon Attorney, which reviews commutation requests for all federal prisoners.¹⁷ For state death sentences, the governor typically holds clemency power, though a few states vest it in a board. Clemency is discretionary and requires no legal error in the original case. It is the one part of the process where considerations beyond the law, such as mercy, rehabilitation, or lingering doubts about guilt, can formally enter the picture.

1
Justia. Tison v. Arizona, 481 US 137 (1987)
2
Office of the Law Revision Counsel. 18 USC 3591 – Sentence of Death
3
Legal Information Institute. Kennedy v. Louisiana
4
Office of the Law Revision Counsel. 10 USC Chapter 47 – Uniform Code of Military Justice
5
Office of the Law Revision Counsel. 18 USC 3593 – Special Hearing to Determine Whether a Sentence of Death Is Justified
6
Office of the Law Revision Counsel. 18 USC 3592 – Mitigating and Aggravating Factors
7
Legal Information Institute. Ring v. Arizona
8
Justia. Hurst v. Florida, 577 US 92 (2016)
9
Justia. Lockett v. Ohio, 438 US 586 (1978)
10
Constitution Annotated. Minors and Death Penalty
11
Legal Information Institute. US Constitution Annotated – Cognitively Disabled and Death Penalty
12
Justia. Ford v. Wainwright, 477 US 399 (1986)
13
Justia. Panetti v. Quarterman, 551 US 930 (2007)
14
Justia. Madison v. Alabama, 586 US (2019)
15
Federal Register. Manner of Federal Executions
16
Office of the Law Revision Counsel. 28 USC 2244 – Finality of Determination
17
U.S. Department of Justice. Apply for Clemency