Back in 2002, the United States Supreme Court ruled that executing defendants who were developmentally disabled (or MR or whatever the preferred term is these days) was cruel and unusual punishment. The case was Atkins v. Virginia. We shouldn't be taking the lives of people who don't understand why they're being punished as they are, who lack the intellectual skills to comprehend what they did wrong or what they could have done instead. Etc., etc. It's the same basic argument for why we don't execute juveniles.
With juvenile defendants, it's easy to draw a bright line rule. If the crime was committed before your 18th birthday, no death penalty. In the case of Atkins defendants, though, the bright line gets pretty blurry. The generally-accepted threshold for being considered developmentally disabled is an IQ of 70. But it's never quite that simple for a number of reasons. First, you give any one person multiple IQ tests and you'll get different numbers every time. We can confidently say someone's true IQ is somewhere in a 5 or 10 number range, but there's no definitive way to pin it down to one number. Second, even after a number range is established, there is still a subjective determination that ultimately has to be made by a court.
In the post-Atkins world, there is still a lot of controversy surrounding individual defendants. Perhaps no state has engendered more controversy on this topic than Georgia. That state's legislature has enacted a law that requires that a criminal defendant making an Atkins claim has to prove his or her lack of intellectual functioning beyond a reasonable doubt. No other state imposes such a burden on defendants. But that burden has been upheld thus far. (See Head v. Hill, 587 S.E.2d 613, 2003.)
So this is where we stand on Monday night, with Warren Lee Hill's execution set for Tuesday, even though all the medical experts who have evaluated Mr. Hill now agree that he should qualify for Atkins protection. Mr. Hill's defense attorney has been fighting this fight for 16 years now and is undoubtedly working frantically now to get some court somewhere to stop this thing. You would think, though, that no one should have to work this hard to keep a man every expert agrees is developmentally disabled from being executed in a nation where our highest court has declared we don't execute the developmentally disabled.