The Supreme Court of the United States has declined to take up cases to clarify the application of principles directed to prevent the execution of prisoners with mental disabilities. The principles were recognized in Atkins v. Virginia,” the 2002 ruling that executing the intellectually disabled violates the Eighth Amendment’s ban on cruel and unusual punishment.
The refusal to clarify the principles assisted Roderick Smith who had been found to come within Atkins v Virginia by rulings below but left the life of David Keen in jeopardy. Keen has been refused the benefit of Atkins v Virginia and remains on death row in Tennessee.
The Bloomberg Law report of the decision not to intervene may be found at this link.