The US Court of Appeals for the Fifth Circuit on Wednesday ordered a federal court to hold an evidentiary hearing to consider whether a man sentenced to death for murder might be mentally retarded. After Michael Wayne Hall was convicted of the 1998 killing of a 19-year-old woman, he claimed at state habeas proceedings that he was mentally retarded. While Hall's state habeas claim was pending in Texas, the Supreme Court decided Atkins v. Virginia, holding that the execution of mentally retarded individuals is unconstitutional and outlining heightened standards for determining a defendant's developmental status. The Fifth Circuit held Wednesday that Hall is entitled to an evidentiary hearing to prove his contentions because:

[T]he facts before us are a core manifestation of a case where the state fails to provide a full and fair hearing and where such a hearing would bring out facts which, if proven true, support habeas relief...[T]he state court's erroneous factfinding and its refusal to accept more than paper submissions despite the development of a new constitutional standard and a lack of guidance from the state on that standard deprived Hall of a full and fair hearing at the state level...Given the material errors in credibility determinations and factfinding at the state level, we are persuaded that the determination of Hall's claim, caught in the immediate uncertainty following Atkins, was so freighted with a risk of error in factfinding that the failure of the district court below to conduct a meaningful hearing was an abuse of discretion in these unusual and unique circumstances.
Concurring in part and dissenting in part, Judge Patrick Higginbotham asserted that the district court should enter an order that unless the state provides Hall with a constitutionally adequate evidentiary hearing within 120 days, Hall will no longer be eligible to receive a death sentence

In August 2007, the European Union urged Texas officials to halt all executions in the state and to consider introducing a moratorium on death sentences. EU officials specifically praised the ruling in Atkins and asked the state to expand it to those with severe mental illness. Texas has since maintained its death-penalty policy, and other states have followed suit. In 29 states, the defendant carries the burden of proving mental retardation in death-penalty cases to receive a lesser sentence.