The Eighth Circuit opinion and the execution of Singleton have to be considered defeats for those who championed the ethical guidelines against psychiatric participation in capital punishment. But as noted, the case is more complicated than those guidelines imagined. At some point Singleton gave up his fight against the death penalty and asked his lawyer not to attempt further appeals. His lawyer reported that judges who conducted the hearings were very concerned that Singleton have informed consent, and he was told more than once in open court that if he took medication voluntarily it might lead to his execution. Nonetheless, at some point Singleton decided to take antipsychotic medication voluntarily because it controlled his symptoms. His lawyer confirmed that he was in fact taking the medication voluntarily in the weeks leading up to his execution. Furthermore, the governor of Arkansas indicated that if Singleton himself requested clemency he would consider granting it. But Singleton did not. According to his lawyer, he had become resigned to his fate.
Given these additional facts, one confronts a different set of ethical questions. Does a psychiatrist who is treating a death row inmate in Singleton's circumstances have an ethical duty to withhold a medical treatment that mitigates suffering and that the patient has decided to accept? One can perhaps imagine a psychiatrist determining that the patient/inmate is incompetent to make such a decision because he fails to appreciate that the treatment will bring about his execution. But a psychiatrist who attempted to make such difficult clinical and ethical determinations would (in my view) be considering the issues that have arisen in physician-assisted suicide and would get little help from organized psychiatry's guidelines on participation in capital punishment, which do not take into account the possibility that the inmate is consenting to treatment because he is resigned to his fate (Code of Medical Ethics, H-140.950 Physician Participation in Capital Punishment). It is important to emphasize that had Singleton continued to refuse medication and allowed his lawyer to attempt further appeals, there may well have been a different ruling.
Although the Singleton case is a defeat, in my experience, organized psychiatry's ethical opposition to participation in the death penalty has played an important role in modifying the law and the practice of capital punishment.