Georgia is just days away from executing a man who, experts said, is mentally disabled.
Unless the Supreme Court intervenes, Warren Hill will be put to death on Monday, according to the Atlantic.
Hill's lawyers have appealed his case to the nation's highest court, which must now decide whether to hear the case.
The death row inmate was previously scheduled to be executed in February, but the 11th U.S. Circuit Court of Appeals intervened. In April, the same court lifted the stay.
The Associated Press reports that Hill was convicted of the 1990 killing of fellow inmate, Joseph Handspike, who was killed with a "nail-studded" board while he slept.
Hill was in prison at the time for killing his girlfriend, Myra Wright.
But, as the American Civil Liberties Union noted in a blogpost on Thursday, "All experts who have evaluated Warren Hill agree that he fits the diagnostic classification of intellectually disabled (formerly called mentally retarded)."
In 2002, the Supreme Court ruled that states could not execute "mentally retarded" inmates because such action constituted cruel and unusual punishment.
But the court left it to the states to decide how to determine whether a defendant was intellectually disabled. Georgia, as the Atlantic reports, has the toughest standard in the country, requiring inmates to prove beyond a reasonable doubt that they are mentally handicapped. Prosecutors argue that Hill has not met this burden of proof.
The state-appointed experts who evaluated Hill initially said he did not qualify as mentally disabled. But, according to the Atlantic, all of them have since come around to the opposite conclusion.
Still, the state now argues that, "Hill has not met his burden of proving retardation under an onerous state standard; that the doctors' new diagnoses are flawed; and that, as a matter of law, they come too late anyway to spare Hill," according to the Atlantic.
The ACLU's executive director, Anthony Romero, denounced the scheduled execution in a blog post.
"Executing this indisputably intellectually disabled man would not only violate our Constitution, but it would be cruel and unjust beyond reason," Romero said.