The strongest arguments against the death penalty rest on documented facts rather than abstract principle: at least 202 people sentenced to die in the United States have been exonerated since 1973, lethal injection has the highest botched-execution rate of any method ever used, capital cases cost states millions of dollars more than life-without-parole prosecutions, and the Supreme Court has acknowledged racial disparities in capital sentencing while declaring them legally unreachable. These are the legal and practical grounds opponents raise when they argue that capital punishment cannot be administered fairly, accurately, or affordably.
The Risk of Executing an Innocent Person
No procedural safeguard in American criminal law is perfect, and in capital cases imperfection is irreversible. At least 202 people sentenced to death in the United States have been exonerated since 1973. That works out to roughly one exoneration for every eight executions carried out.1Death Penalty Information Center. Botched Executions Each one represents a person the state was prepared to kill for a crime they did not commit, and the number does not include people who were executed before exonerating evidence could emerge.
The system has responded by building in extra layers of review. All fifty states now have statutes allowing convicted prisoners to seek DNA testing of biological evidence, and federal prisoners can pursue testing under the Innocence Protection Act of 2004.2Office of the Law Revision Counsel. 18 USC 3591 – Sentence of Death Capital cases carry longer trials, mandatory appeals, and specialized defense teams, with the average death row prisoner waiting well over a decade between sentencing and execution or exoneration. Those safeguards exist because the stakes are irreversible, but their existence is itself an admission: the ordinary trial process is not reliable enough to trust with a life.
Racial Disparities the Courts Have Refused to Fix
The Fourteenth Amendment’s Equal Protection Clause requires equal treatment under the law regardless of race, but statistical evidence has long shown that race shapes who gets a death sentence. The most prominent research on this question is the Baldus study, examined in McCleskey v. Kemp. That study analyzed over 2,000 murder cases in Georgia and found that defendants who killed white victims were significantly more likely to receive the death penalty than those who killed Black victims, and that Black defendants who killed white victims faced the highest probability of a death sentence.3Justia U.S. Supreme Court Center. McCleskey v Kemp, 481 US 279 (1987)
The Court acknowledged those findings and ruled against the defendant anyway. It held that statistical evidence of system-wide racial disparities is not enough to prove a constitutional violation. A defendant must show that intentional discrimination occurred in their specific case, whether by a particular prosecutor, judge, or jury. Without recorded statements or other direct evidence of racial animus, that bar is almost impossible to clear. McCleskey remains one of the most criticized death penalty decisions precisely because it concedes a problem and then declares it beyond the reach of constitutional challenge.
Jury selection compounds the concern. Prospective jurors who are categorically opposed to the death penalty are removed from capital cases during a process called “death qualification.” Research consistently shows that death-qualified juries are less racially diverse and more conviction-prone than juries selected without this filter. The Court has tried to police racial bias in individual strikes through Batson v. Kentucky, which prohibits prosecutors from using peremptory challenges to strike jurors based on race.4Legal Information Institute. Batson v Kentucky, 476 US 79 (1986) Proving that a strike was racially motivated rather than based on the prosecutor’s stated neutral reason remains difficult in practice.
Botched Executions and the Method Problem
Lethal injection is the primary execution method in virtually every state that authorizes the death penalty, and it has the worst track record of any method ever used.5National Conference of State Legislatures. States and Capital Punishment Research covering executions from 1890 to 2010 found that lethal injection had a botched-execution rate of roughly 7%, compared to about 5% for lethal gas and under 2% for electrocution. More recent data from the post-Furman era shows that 50 out of 63 identified botched or problematic executions involved lethal injection, including six cases where the procedure was halted entirely because medical staff could not establish an IV line.1Death Penalty Information Center. Botched Executions
Challenging a method in court is almost impossibly difficult. In Glossip v. Gross, the Supreme Court ruled that a prisoner must show both that the method creates a substantial risk of severe pain and that a known, available alternative would significantly reduce that risk.6Justia U.S. Supreme Court Center. Glossip v Gross, 576 US 863 (2015) Bucklew v. Precythe reinforced that requirement in 2019, holding that identifying a feasible alternative method is a threshold element of any Eighth Amendment method-of-execution claim.7Justia U.S. Supreme Court Center. Bucklew v Precythe, 587 US (2019) Critics describe this as a Catch-22: a prisoner cannot simply argue that his execution will be torture, he must essentially propose a better way for the state to kill him.
Supply has become its own problem. The European Union expanded its export restrictions in 2011 to prevent drugs like sodium thiopental and pentobarbital from being shipped to countries that use them for executions. States have increasingly turned to compounding pharmacies and secretive drug protocols, prompting further litigation. Five states now authorize nitrogen hypoxia as an execution method, though it remains legally controversial and has seen extremely limited use.
Vulnerable Defendants the System Still Reaches
The Supreme Court has carved out categorical exemptions for groups the Constitution treats as less culpable, but gaps remain and the existing lines are not uniformly enforced.
Atkins v. Virginia held that executing a person with an intellectual disability violates the Eighth Amendment. The majority reasoned that people with intellectual disabilities have diminished capacity to understand their actions, control their impulses, and assist in their own defense, making them less deserving of the ultimate punishment and less likely to be deterred by it.8Justia U.S. Supreme Court Center. Atkins v Virginia, 536 US 304 (2002) The Court left states to define intellectual disability for this purpose, which produced wildly inconsistent standards. Florida adopted a rigid IQ cutoff of 70 and refused to consider any defendant who scored above that number, an approach the Court struck down in Hall v. Florida on the ground that intellectual disability “is a condition, not a number.”9Justia U.S. Supreme Court Center. Hall v Florida, 572 US 701 (2014) The need for that correction tells you how aggressively some states had been pushing the line.
In Roper v. Simmons, the Court banned the execution of anyone who was under 18 at the time of the crime, citing juveniles’ lack of maturity, their greater vulnerability to outside pressure, and personalities that are still forming.10FindLaw. Roper v Simmons
The clearest remaining gap involves severe mental illness. The Court held in Ford v. Wainwright that the Eighth Amendment bars the execution of someone who is so mentally ill at the time of the scheduled execution that they cannot understand what is happening or why the government is putting them to death. That protection applies only at the moment of execution. There is no federal constitutional ban on sentencing a person with a serious mental illness to death, even if that illness was present when the crime occurred. The categorical protections of Atkins and Roper have never been extended to this population.
The Cost Argument
Death penalty cases cost dramatically more than comparable non-capital prosecutions. Studies across multiple states have found that capital cases run between two and a half to ten times more expensive, with some analyses placing the additional cost at $1 million to $3 million per case above what a life-without-parole prosecution would cost. Capital trials last roughly four times longer than non-capital murder trials, requiring more attorneys, more expert witnesses, more investigation, and more court resources.11Death Penalty Information Center. Costs
The expense does not end at sentencing. Mandatory appeals, post-conviction proceedings, and the higher cost of housing death row inmates in specialized facilities continue adding to the total. One frequently cited comparison found that housing a death-sentenced prisoner costs about twice as much per year as housing someone in general population. For states that rarely carry out executions, the math is especially unfavorable: they bear the full cost of the capital prosecution and decades of death row confinement, often without ever reaching an execution. Several states have cited financial strain as a reason to reconsider or repeal their death penalty statutes.
Evolving Standards and International Isolation
The Eighth Amendment’s prohibition on “cruel and unusual punishments” is not frozen in 1791. In Trop v. Dulles (1958), the Court declared that the amendment “must draw its meaning from the evolving standards of decency that mark the progress of a maturing society.”12Legal Information Institute. US Constitution Annotated – Amdt8.3.2 Evolving Standard That phrase has been quoted in nearly every major death penalty case since. As more states abolish capital punishment and fewer juries impose it, the argument that the practice has become constitutionally “unusual” grows stronger on its own terms.
The United States is an outlier among wealthy democracies. Most of Europe, South America, and an increasing number of nations worldwide have abolished capital punishment entirely. The Second Optional Protocol to the International Covenant on Civil and Political Rights specifically aims to end the use of the death penalty among member nations.13OHCHR. Second Optional Protocol to the International Covenant on Civil and Political Rights, Aiming at the Abolition of the Death Penalty The United States has not ratified the protocol, though it is party to the broader covenant.
That isolation carries practical consequences. The EU’s 2011 export restrictions have made it difficult for states to obtain execution chemicals through legitimate pharmaceutical channels. Countries routinely refuse to extradite suspects to the United States without assurances that the death penalty will not be sought, forcing U.S. prosecutors to waive capital charges to secure the return of fugitives. Supreme Court justices have cited global trends in their written opinions, and under the Trop framework the standards the Court measures are not limited to American opinion.14Justia U.S. Supreme Court Center. Trop v Dulles, 356 US 86 (1958)
Clemency and Moratoriums Signal a System Unsure of Itself
After every court appeal has been exhausted, the last safeguard against an execution is executive clemency. For federal death row prisoners, the President holds sole authority to grant a pardon or commute a death sentence under Article II of the Constitution.15Congress.gov. Overview of Pardon Power For state prisoners, the power belongs to the governor, sometimes acting alone and sometimes with a clemency board.
Clemency exists as a formal admission that the legal process can fail. A governor or president can act on evidence that falls outside the narrow grounds for judicial relief, including doubts about guilt, disproportionate sentencing, or evidence of rehabilitation. Several states maintain governor-imposed moratoriums on executions while the death penalty remains on their books, including California, Oregon, and Pennsylvania, effectively pausing the machinery without repealing the law. The federal system has followed a similar pattern. Attorney General Merrick Garland imposed a moratorium on federal executions during the Biden administration, and Attorney General Pamela Bondi lifted that moratorium in February 2025. No federal execution has been carried out since 2021. When officials entrusted with carrying out a punishment repeatedly decide to pause it, that pattern is itself part of the case against it.