For Defendants With Retardation, Procedures Vary: Expert witnesses in death penalty cases must know standards of proof differ from state to state.

SAN FRANCISCO — The U.S. Supreme Court decision that executing mentally retarded offenders is unconstitutional provided little guidance on how to implement the ruling. The result has been a mishmash of procedures that vary widely from state to state, Dr. Clarence Watson and Dr. Kenneth Weiss said at the annual meeting of the American College of Forensic Psychiatry.