Rock v. Arkansas 483 U.S. 44, 107 S.Ct. 2704, 97 L.Ed.2d 37 (1987)
Rock got into an argument with her abusive husband. She
called the police, who arrived at the scene to find the husband dead, and
Rock holding a gun, completely hysterical.
Rock professed that she could not remember what happened.
Her attorney took her to a hypnotist, and under hypnosis, she stated that
she was holding the gun, but never actually pulled the trigger.
A gun expert was brought in, and he found that the gun
was defective and prone to firing when knocked around.
At trial, Rock attempted to introduce the
hypnotically-derived testimony.
The prosecution objected on the grounds that the
testimony was inadmissible.
The prosecution argued that a defendant's testimony is
limited to matters that they can prove were remembered before hypnosis.
The Trial Judge excluded the testimony, but allowed the
gun expert's analysis into evidence.
Arkansas has a State law that excluded
hypnotically-derived testimony on the grounds that it was inherently
unreliable.
The Trial Court convicted Rock of manslaughter. She
appealed.
The Arkansas Supreme Court affirmed. Rock appealed.
Rock argued that the limitations on her testimony
violated her right to present a defense. However, the Arkansas Supreme
Court found that "the dangers of admitting this kind of testimony
far outweigh whatever probative value it may have."
The US Supreme Court reversed and remanded for a new
trial.
The US Supreme Court found that under the 6th
Amendment a defendant has a right to testify in their own defense.
The Court found that the Arkansas Supreme Court failed to perform a
constitutional analysis.
While the US Supreme Court noted that
hypnotically-derived testimony is often incorrect, it isn't always
incorrect, and so Arkansas' absolute bar to hypnotically-derived
testimony was an impermissible and arbitrary violation of the 6th
Amendment right to testify in your own defense.
The Court noted that in this case, the gun expert's
findings corroborated Rock's hypnotically-derived memory, which is a
good argument for admissibility.
In a dissent, it was argued that an individual's right to
represent evidence is always subject to reasonable restrictions and that
the right to present evidence is not absolute. There is a convincing
argument that hypnotically-derived testimony is inherently unreliable, and
therefore it is reasonable for Arkansas to bar it from admissibility.