Opinion of the Court
U. S., at 962 (remanding the case to consider expert evidence on whether the prisoner’s delusions did so). And much the same is true of dementia. That mental condition can cause such disorientation and cognitive decline as to prevent a person from sustaining a rational understanding of why the State wants to execute him. See supra, at 11–12. But dementia also has milder forms, which allow a person to preserve that understanding. Hence the need–for dementia as for delusions as for any other mental disorder–to attend to the particular circumstances of a case and make the precise judgment Panetti requires.
III
The only question left–and the only one on which the parties now disagree–is whether Madison’s execution may go forward based on the state court’s decision below. Madison’s counsel says it cannot because that ruling was tainted by legal error–specifically, the idea that only delusions, and not dementia, can support a finding of mental incompetency. See Tr. of Oral Arg. 12, 21, 25, 27. Alabama counters that the state court did not rely on that (concededly) incorrect view of the law. See id., at 37–41. But we come away at the least unsure whether that is so–especially given Alabama’s evidence and arguments in the state court.
As noted earlier, the 2018 ruling we review today contains only one sentence of explanation. See supra, at 7–8. It states that Madison “did not provide a substantial threshold showing of insanity[ ] sufficient to convince this Court to stay the execution.” App. A to Pet. for Cert. If the state court used the word “insanity” to refer to a delusional disorder, then error occurred: The court would have denied a stay on the ground that Madison did not have that specific kind of mental illness. And the likelihood that the court made that mistake is heightened by the State’s emphasis, at that stage of the proceedings (as at
