Eyewitness identification is widely considered to be one of the most powerful pieces of evidence a prosecutor can offer at a criminal trial.  But psychologists continue to debate whether witnesses to a crime can accurately relay what they saw.  The Supreme Court has debated the due process implications of such unreliable evidence, and with oral arguments in Perry v. New Hampshire scheduled for later this week, the Court will revisit the issue once again.

In 2008, Joffre Ullon called police to report that his wife had seen a man breaking into cars outside their Nashua, New Hampshire apartment complex.  When police arrived at the scene, they discovered Barion Perry carrying two car stereo amplifiers across the complex’s parking lot.  Perry told police that he had found the amplifiers on the ground and was simply moving them out of the way.

While Perry was talking to police, Ullon and his wife were discussing what they had seen with another Nashua officer.  Ullon’s wife stated that the man she had seen breaking into the cars was “tall” and “African-American.” When pressed for details, Ullon’s wife looked out the window, pointed to Perry, and identified him as the culprit.  At the time of the identification, Perry was standing next to a Nashua police officer.

At trial, Perry moved to exclude the identification, claiming that the evidence’s admission would violate his due process rights.  Perry asserted that his proximity to police at the time of the identification colored the witness’s memory by suggesting that he was a person of interest in the police’s investigation.  The trial court disagreed.  Without ruling on whether the circumstances surrounding Perry’s ID were suggestive of guilt, the court asserted that Perry could not mount a due process claim because the suggestive circumstances were not “intentionally orchestrated by police.”  A defendant may challenge a witness’s ID only if its reliability is called into question by “improper state action.”  Here, the circumstances of which Perry complained were a matter of happenstance, meriting the identification’s admission.

The issue before the Supreme Court is whether eyewitness identifications must be excluded whenever the identification was made under circumstances that make the ID unreliable.  As it stands, exclusion is mandated only when police themselves are responsible for the suggestive circumstances.

The question turns in large part on the ill the exclusionary rule is designed to cure.  Perry argues that the Court should be concerned with reliability.  “It is the likelihood of misidentification which violates the defendant’s right to due process,” Perry declares.  In contrast, the State claims that the exclusion of unreliable eyewitness testimony is merited only to the extent that it deters police misconduct.  Arguing on behalf of New Hampshire, the United States asserts, “Police involvement is a necessary prerequisite for a due process analysis into the reliability of an identification.”  Only after a court has determined that police misconduct created circumstances “unnecessarily suggestive” of a defendant’s guilt need the court engage in an inquiry into the reliability of the resulting identification.

New Hampshire’s rule is the easier one to administer.  Assessing the reliability of an ID is a tricky task.  Indeed, Perry does not propose a standard for answering “how suggestive is too suggestive?”  By saving the reliability inquiry until after a court has assessed police misconduct, judges can screen out many complicated due process claims.

Adopting such a rule, however, leaves the Court in an awkward position.  In 1967, the Court conceded: “The vagaries of eyewitness identification are well-known; the annals of criminal law are rife with instances of mistaken identification.”  Modern psychology has only confirmed the Court’s intuition.  Study after study has substantiated the inaccuracy of eyewitness testimony, such that tighter rules must be enacted before it can be admitted at criminal trials.  Perry presents an opportunity for relatively modest reformation: when a defendant can point to concrete facts undermining the reliability of an ID, the prosecution must turn to alternative evidence in order to prove its case.  At least in this narrow class of cases, administrability must give way to accuracy.