On Monday, the Supreme Court ruled against hearing the appeal of death row inmate Ernest Johnson, who is seeking death by firing squad instead of lethal injection. The conservative majority justices did not explain the court's decision.

Before the Supreme Court denied Johnston's request for a hearing, a lower court had upheld Missouri's refusal to execute him via nitrogen gas, another state-approved method for execution authorized by state law. The lower court ruled Johnson may not amend his lawsuit to request a firing squad in Missouri.

However, other states, including Mississippi, Oklahoma, and Utah allow death by firing squad. South Carolina just passed a law for inmates to choose between death by firing squad or the electric chair if the drugs used for lethal injection are unavailable.

There have been only three convicted death row inmates killed by firing squads in the U.S. since 1976. The last convict killed by firing squad was in Utah in 2010 when convicted murderer Ronnie Lee Gardner was executed.

The Missouri inmate Johnson was denied a hearing by the six conservatives on the Supreme Court, triggering protests from the court's sitting liberal justices. Johnson requested the change of death from lethal injection to the firing squad to avoid unnecessary prolonged pain.

Justice Sonia Sotomayor wrote a blistering dissent for herself and fellow liberal justices Stephen G. Breyer and Elena Kagan, saying, "Missouri is now free to execute Johnson in a manner that, at this stage of the litigation, we must assume will be akin to torture given his unique medical condition."

Johnson suffers from epilepsy and brain damage resulting from a brain tumor. In his 2016 complaint, Sotomayor noted in her dissent that Johnson alleged he will "experience excruciating seizures if Missouri executes him by lethal injection of the drug pentobarbital (and) that Missouri should execute him by nitrogen gas instead, a method of execution authorized by state law. In 2018, the Eighth Circuit held that Johnson fully stated a claim for relief under the Eighth Amendment."

The death row inmate, convicted of murdering three people, alleges he will suffer from "extremely painful seizures if he is killed by lethal injection by Missouri's drug of choice drug pentobarbital. Johnson states this is a violation of his Constitutional rights that prohibit cruel and unusual punishment."

Federal executions in the U.S. were reinstated for the first time in seventeen years in 2020 since they had last occurred in 2003.

The Supreme Court's unsigned 2020 decision noted "the plaintiffs have not established that they are likely to succeed on the merits of their Eighth Amendment claim" and "that claim faces an exceedingly high bar."

The Eighth Amendment bars cruel and unusual punishment. Since 1976, The Supreme Court has ruled capital punishment itself is not a violation of the Eighth Amendment, but that some applications for the death penalty, such as executing mentally ill death row inmates, are "cruel and unusual."

The Supreme Court has offered a variety of decisions considering the death penalty for decades. Though the death penalty is legal in the U.S., there are specific circumstances regarding when and how this penalty may be carried out. The Eighth Amendment's ban on cruel and unusual punishment impacts courts on when the death penalty may be legally used. However, the Fourteenth Amendment's due process clause is also a vital consideration for courts in regards to a death penalty decision.

In modern times, death penalty jurisprudence can be traced to 1972, when the Supreme Court decided the case of Furman v. Georgia. The outcome of that ruling was to place a moratorium on all executions nationwide for the next four years. The court returned to the issue in 1976 in Gregg v. Georgia, a case that held the death penalty can be constitutional if carried out properly. In the aftermath of Gregg and its progeny, the death penalty has been ruled unconstitutional in cases involving mentally handicapped or juvenile defendants. The crime of rape and so-called felony murder (when a death occurs during the commission of a felony) have been held not to be capital crimes. Also, state or federal laws cannot impose a mandatory death sentence for the commission of a crime. Instead, courts and juries must evaluate both aggravating and mitigating circumstances during the penalty phase of a murder trial to determine whether the death penalty in a given case is proper.

States are not permitted to carry out the death penalty in an arbitrary or capricious manner. Whether and in what manner executions can be lawfully performed is an issue that will likely continue to be visited in the courts.