"How should states decide if someone convicted of a crime has an intellectual disability, when the answer means life or death?"

The title of this post is the first sentence of this lengthy USA Today article headlined "Supreme Court to revisit death penalty for mentally disabled."  Here is more from an effective review of the challenging capital procedure issues now before SCOTUS:

In its 6-3 decision in Atkins v. Virginia, authored by Justice John Paul Stevens, the court prohibited states from executing anyone with "mental retardation."  Mental health professionals define it as substantial limitations in intellectual functions such as reasoning or problem-solving, limitations in adaptive behavior or "street smarts," and evidence of the condition before age 18.  (Mental retardation is the term used in law, but most clinicians and The Associated Press refer to the condition as intellectual disability.)

After the decision, most states stuck with the three-pronged clinical definition, but Florida, Georgia, Mississippi and Texas set their own standards. Under Florida's law, if you have an IQ over 70, you're eligible for execution regardless of intellectual function or adaptive behavior.

Freddie Lee Hall, who has been on Florida's death row for more than 30 years and scored in the mid-70s on IQ tests, is arguing the state's standard amounts to unconstitutional punishment.  Most likely, the case won't result in a dramatic shift in national criminal justice policy, but will further clarify who should and should not be eligible for execution, said Ronald Tabak, an attorney who has represented multiple clients with intellectual disabilities and chairs the American Bar Association's death penalty committee....

The court's makeup has shifted since the 2002 Atkins decision.  But if the justices split along ideological lines, the vote could favor Hall, assuming that swing vote Justice Anthony Kennedy sides with Hall, as he did with Atkins in 2002.  Arguments are set for March 3.

Similar cases are percolating beyond Florida.  In Georgia, death row inmate Warren Hill is fighting execution based on substantial evidence that he is intellectually disabled. In Texas, where the courts use an anecdotal seven-part test largely based on the characteristics of the fictional character Lennie from John Steinbeck's novel "Of Mice and Men" to determine intellectual disability, multiple prisoners have been executed in recent years even when they've scored well below 70 on IQ tests.

Last year, Texas executed Marvin Wilson, who was convicted of murder in 1994, even though he had an IQ of 61.  In 2010, Virginia executed Teresa Lewis for her role in a murder-for-hire scheme, even though she had an IQ of 72 and her co-conspirators admitted Lewis did not plan the murder....

Still, the Atkins decision has had an impact on executions. At least 98 people have had their death sentence changed since 2002 by proving that they were intellectually disabled, according to data from the Death Penalty Information Center.  By their count, in the 18 years before the Atkins decision, at least 44 people who likely suffered from intellectual disabilities were executed.