More than a decade after the U.S. Supreme Court’s landmark decision barring execution of the mentally retarded, the justices on Monday agreed to examine how to determine mental disability in capital cases.

The court granted review in Hall v. Florida, a challenge to the state’s law that, in effect, sets a bright-line cutoff of an IQ of 70 or below to qualify as mentally retarded and exempt from the death penalty. Freddie Hall was convicted and sentenced to death for the 1978 murder of Karol Hurst, seven months pregnant, whose car he and another man hijacked to use in a robbery. The state’s governor signed his first death warrant in 1982.