Brian Kammer said Monday he is “horrified and outraged” by the board’s decision. His client, Warren Lee Hill, was initially serving a life sentence in 1990 for the 1986 killing of his girlfriend when he killed a fellow inmate. A jury in 1991 convicted Hill of murder and sentenced him to death.

An earlier report by the Atlanta Journal Constitution helps explain why, even though Hill was deemed mentally disabled, he still faces execution:

Georgia enacted the groundbreaking law banning the execution of those who meet the legal criteria for mental retardation in 1988, more than a decade before the U.S. Supreme Court prohibited the practice nationwide.

Hill’s problem is that a judge found him more likely than not to be mentally disabled. Georgia’s law requires capital defendants to clear a far more difficult legal threshold — proving it beyond a reasonable doubt.

If Georgia executes Hill, it will set an unfathomable precedent:

Richard Dieter, executive director of the Death Penalty Information Center, which tracks capital cases nationwide, said he knew of no other case comparable to Hill’s. Forty-four people with evidence of mental retardation have been executed since 1976, but that was before the Supreme Court’s ban in 2002, he said.

Since Hill’s execution is scheduled for Wednesday, it looks as if Georgia is set to become the first state to ignore the Supreme Court’s ban on executing mentally retarded people.