By Lawrence Hurley
WASHINGTON (Reuters) - A majority of U.S. Supreme Court justices on Tuesday appeared ready to side with a man sentenced to death for a 1980 Houston murder who is challenging how Texas gauges whether a defendant has intellectual disabilities that would preclude execution.
The Supreme Court ruled in 2002 that the execution of people who are intellectually disabled violates the U.S. Constitution's ban on cruel and unusual punishment. At issue in the arguments the eight justices heard on Tuesday was whether Texas is using an obsolete standard to assess whether a defendant is intellectually disabled.
Bobby Moore, convicted at age 20 of fatally shooting a 70-year-old grocery clerk during a 1980 Houston robbery, is challenging his sentence in Texas, which carries out more executions than any other U.S. state.
Moore's lawyers contend their client is intellectually disabled and should be spared execution. They argued that a lower court that upheld his sentence wrongly used an "outdated" 24-year-old definition used in Texas when it determined he was not intellectually disabled.
Moore's appeal focused on how judges should weigh medical evidence of intellectual disability. His lawyers said that a lower court found that Moore's IQ of 70 was "within the range of mild mental retardation."
Based on questions asked during the argument, the justices, equally divided between liberals and conservatives, appeared likely to rule for Moore, 57.
Justice Anthony Kennedy, a conservative who sometimes sides with the liberals, looked likely to be the key vote. Kennedy and two other current justices were in the majority in the 2002 ruling precluding executing people with an intellectual disability.
At one point during the argument, Kennedy said that the state appeals court precedent on which Texas relies was intended to "really limit" the definition of intellectual disability.
Texas Solicitor General Scott Keller responded that the state court has "never said that the purpose ... is to screen out individuals and deny them relief."
"But isn't that the effect?" Kennedy asked.
Justice Elena Kagan, a liberal, said the Texas standards appeared to reflect a decision by the state court to reject expert clinical findings because "they don't reflect what Texas citizens think."
The Supreme Court's justices have differed among themselves over capital punishment but the court has shown no indication it will take up the broader question of the whether the death penalty itself violates the Constitution. Liberal justices Stephen Breyer and Ruth Bader Ginsburg have said the way the death penalty is implemented may be unconstitutional, in part because of differences from state to state.
Breyer hinted at those concerns during Tuesday's argument. He said it may not be possible to set an intellectual disability standard that is applied uniformly nationwide, meaning there will be "disparities and uncertainties" and "people who are alike treated differently."
The high court on Oct. 5 heard arguments in another Texas death penalty case. In that one, the justices appeared poised to rule in favor of black convicted murderer Duane Buck, who is seeking to avoid execution after his own trial lawyer called an expert witness who testified Buck was more likely to be dangerous in the future because of his race.
Rulings in both cases are due by the end of June.
(Reporting by Lawrence Hurley; Editing by Will Dunham)