Florida's statute, as interpreted by the state supreme court, sets the definition of developmental disability at an IQ score of 70 or below. With anything higher, the defendant cannot put on other evidence to show he is intellectually disabled. Moreover, the state does not allow use of the standard error of measurement that is deemed inherent in IQ tests.

Hall's various test scores added up to an average of more than 70, but no more than 75, meaning that he would qualify as having a disability if the state had used the standard five-point error of measurement. Without that statistical norm, however, Hall's lawyers were barred from putting on any other evidence of disability — for example, school records that consistently identified Hall as being mentally retarded.

"Florida's position is inconsistent with the views of all the mental disability organizations and professional organizations that are involved in the definition of mental retardation," says Jim Ellis, a longtime advocate for people with mental disabilities. He has also filed a brief in the case.

Allowing states to redefine "mental retardation" in defiance of professional standards, he argues, is nothing more than a way to undo the Supreme Court's 2002 ruling.

"The direct impact is only on Florida and those handful of states that have adopted this rigid and arbitrary rule," said James Ellis of the University of New Mexico School of Law, who argued and won the 2002 decision.

"But, more broadly, the way in which the majority opinion makes clear that in making Atkins decisions courts have to be open to a wider range of evidence about whether this person has intellectual disability, including evidence about impaired functioning, may have implications in states beyond the handful who are clearly out of compliance today," he said.

A University of New Mexico law professor and nine of his students played a pivotal role in Tuesday's U.S. Supreme Court decision striking down a Florida law that set a minimum IQ of 70 as a benchmark in determining whether a convicted murderer can be executed.

Distinguished Professor Jim Ellis of the UNM School of Law, three other faculty members and the student volunteers prepared a friend-of-the-court brief in support of Freddie Lee Hall in Hall vs. Florida, which was argued before the high court in March. At issue was whether the Florida law's refusal to accept the scientific error of measurement in IQ testing might lead to the execution of intellectually disabled individuals convicted of murder.

After the decision was announced, Ellis said the legal team is "very gratified that the court endorsed the position we had taken on behalf of the national disability organizations that all evidence needs to be considered."

The high court sent the case back to state courts to determine again Hall's level of intellectual deficiency. The justices noted his inability to function socially and the "horrible" childhood he had suffered through, Ellis said.