Several U.S. Supreme Court rulings over the past two decades have narrowed the death penalty’s application in the states. Based on the Eighth Amendment’s ban on cruel and unusual punishment, the high court abolished the death penalty for intellectually disabled offenders in 2002, for juvenile offenders in 2005 and, in 2008, for raping a child when death is not the intended or actual result.
The 2002 Atkins v. Virginia decision categorically excluded individuals with intellectual disabilities from being eligible for capital punishment. This decision was largely driven by state legislative trends at the time and has had possibly the most significant impact on the states since it was decided.
Just 13 years prior to the Atkins decision, the U.S. Supreme Court, in Penry v. Lynaugh, declined to ban death sentences for individuals with intellectual disability. The court’s opinion in Atkins recognized this change in course by pointing to momentum in the states to statutorily exclude these individuals. In the intervening years between decisions, 18 states had enacted an exclusion. The court left it to the states to craft standards for determining who qualified for exclusion.
Atkins forced many states to amend their laws, but the lack of a clear standard for determining intellectual disability led to additional litigation. Subsequent U.S. Supreme Court cases struck down statutes adopted by Florida and Texas. Since 2015, at least nine state enactments have modernized language related to the standard for exclusion.

Source: Atkins v. Virginia, 2002
2. Methods of Execution
Lethal injection is currently the primary method of execution in all 29 states that allow capital punishment. Texas was the first state to use the method, in 1982.
In a 2008 case, Baze v. Rees, the U.S. Supreme Court approved a three-drug combination of (1) sodium thiopental, a sedative that induces unconsciousness, (2) pancuronium bromide, a muscle relaxer that induces paralysis, stopping respiration, and (3) potassium chloride, which causes cardiac arrest.
This was the same three-drug combination that was used in the first lethal injection execution, and at the time of the Baze opinion 30 states were using that exact mixture. The court’s opinion also made it apparent that “substantially similar” drug combinations would be legally acceptable.
Since the Baze opinion, lethal injection drugs have become increasingly difficult for states to purchase due to stopped production and manufacturers’ refusal to sell to states for the purpose of execution. States have used new drugs or turned to compounding pharmacies in order to carry out executions.
Through 2009, most executions were carried out using the same formula approved in Baze. After that time, difficulties accessing drugs led some states to start using new drugs and combinations of substances. For example, Nebraska created a new formula using the opioid fentanyl and became the first state, in August 2018, to use it in an execution. Fentanyl has become notorious for its lethality, driving up overdose deaths in the opioid epidemic. Other new substances used have included cisatracurium besylate, diazepam, etomidate, fentanyl citrate, hydromorphone, midazolam, pentobarbital and potassium acetate.
States have also brought back or introduced new methods of execution. In 2015, Oklahoma became the first state to legalize executions by nitrogen hypoxia (asphyxiation). By law, if nitrogen hypoxia and traditional lethal drugs are unavailable, officials may turn to electrocution or the firing squad, which lawmakers legalized as alternative back-up methods. Mississippi enacted a substantially similar law in 2017, as did Alabama in 2018, though lawmakers there elected to let offenders choose nitrogen hypoxia over lethal injection even when the latter is available.
In total, 16 states have a secondary method of execution authorized by statute. Laws in Alabama, Arkansas, Mississippi, New Hampshire, Oklahoma, South Carolina, Tennessee, Utah and Wyoming provide a secondary option if lethal injection is found to be unconstitutional and/or unavailable. Arizona, Kentucky, Tennessee and Utah all have a choice of secondary methods for offenders who were sentenced before the introduction of lethal injection. And Alabama, California, Florida, Missouri, South Carolina, Virginia and Washington have other methods available if the offender requests an alternative. Secondary methods of execution include electrocution, lethal gas, hanging, nitrogen hypoxia and firing squad.
Secondary Methods of Execution
States with statutory secondary methods of execution that can be used by election or out of necessity due to unconstitutionality of lethal injection.
Secondary Methods of Execution
State |
Statute |
Secondary methods |
Alabama |
§15-18-82.1 |
Electrocution
Nitrogen Hypoxia |
Arizona |
§13-757 |
Lethal Gas |
Arkansas |
§5-4-617 |
Electrocution |
California |
Penal Code §3604 |
Lethal Gas |
Florida |
§922.105 |
Electrocution |
Kentucky |
§431.220 |
Electrocution |
Missouri |
§546.720 |
Lethal Gas |
Mississippi |
§99-19-51 |
Nitrogen Hypoxia
Electrocution
Firing Squad |
New Hampshire |
§630:5 |
Hanging |
Oklahoma |
Title 22 §1014 |
Nitrogen Hypoxia
Electrocution
Firing Squad |
South Carolina |
§24-3-530 |
Electrocution |
Tennessee |
§40-23-114 |
Electrocution |
Utah |
§77-18-5.5 |
Firing Squad |
Virginia |
§53.1-234 |
Electrocution |
Washington |
§10.95.180 |
Hanging |
Wyoming |
§7-13-904 |
Lethal Gas |
Source: NCSL, 2019
3. Confidentiality Laws
In addition to adopting secondary methods of execution, states have also tried to get executions back on track by enacting and expanding confidentiality laws. These efforts aim to keep various aspects of executions, including sources of drugs and identities of participants, a secret.
Historically, states have relied on general exceptions to public information laws to keep certain information about executions confidential, and statutes shielding the identity of executioners have been on the books for years. However, increasing difficulty in sourcing execution drugs has led states to enact or expand confidentiality laws specific to capital punishment. Twenty-two states have passed confidentiality laws specific to capital punishment. The majority of laws enacted in the last decade aimed to expand the information that is kept secret, mainly the source of execution drugs.
Many of these more specific laws have been heavily litigated in recent years. Notably, litigation of these laws extends beyond appeals filed by condemned inmates arguing against cruel and unusual punishment on Eighth Amendment and 14th Amendment grounds. Members of the press and civil rights groups have filed cases to gain access to information through freedom of information laws. Plaintiffs have also argued cases using the First Amendment. So far litigation hasn’t been overwhelmingly successful, and the U.S. Supreme Court has declined to review the cases that have reached it.

4. Abolition
Of the 37 states that reenacted capital sentencing schemes following the 1976 U.S. Supreme Court cases ending the national de facto moratorium, six states subsequently repealed their laws. New Jersey was the first in 2007, followed by New Mexico in 2009, Illinois in 2011, Connecticut in 2012, Maryland in 2013 and New Hampshire in 2019. Additionally, state court actions without subsequent legislative changes have essentially ended the practice. This is the case currently in Delaware, Massachusetts, New York, Rhode Island and Washington.

Voters have also had a direct impact on the status of capital punishment in the states. Ballot questions have reinstated capital punishment following legislative repeal and state court action in a couple of states. For example, the Nebraska Legislature abolished capital punishment in 2015 and a statewide vote the following year reinstated the law. In Oregon, voters have repealed capital punishment twice, once in 1914 and again in 1964. Voters have also restored capital punishment twice, once in 1920 and again in 1978. The law adopted in 1978 was later found to be unconstitutional by the Oregon Supreme Court in 1981. Once again, voters brought back the practice in 1984, changing the law to address the constitutional issues raised by the court.
Like Oregon, the states that have elected to retain capital punishment have had to change their laws over time to comply with litigation outcomes and address logistical issues like limited access to execution drugs.
States have used moratoriums on executions to provide time to evaluate and modify laws and execution procedures. Moratoriums can be for short periods of time or they can be put in place indefinitely. For example, Oklahoma used a brief moratorium starting in late 2015, to allow time for a grand jury to investigate problems with recent executions, including departures from execution protocols. Other states have applied longer moratoriums. Illinois had one in place for more than a decade prior to the repeal of capital punishment. Currently, California, Colorado, Oregon, Pennsylvania and Washington all have indefinite moratoriums in place.