COLUMBIA, S.C. - The state Supreme Court says judges in death penalty cases should decide whether a defendant is mentally retarded.

That determination is important because prosecutors are barred from seeking the death penalty against the mentally retarded following a U.S. Supreme Court decision.

A judge will make a ruling in a separate hearing before the trial starts.

Lawyers for six death row inmates and a man awaiting a death penalty trial had asked the justices to have a jury determine if a defendant is mentally retarded. Legal experts say juries are often more sympathetic than judges.

The justices also ruled Monday that even if a judge finds a defendant is not mentally retarded, defense lawyers can still introduce evidence to the jury that the defendant had mental retardation at the time of the crime.

If the jury decides that was a mitigating factor in the case, a death sentence could not be imposed.

The justices also decided that anyone already on death row who wants to argue he was mentally retarded at the time of the crime can go through the normal post-conviction relief procedure.

Defense lawyers had wanted to set up a separate set of hearings for those men. They say at least 10 of the more than 70 men on South Carolina's death row could be affected.

The court refused a request by defense lawyers to alter the definition of mental retardation, saying that could only be done by lawmakers.