Chapter 9 in Criminal Procedure by Samaha, "Identification Procedures"
Before 1967, the court had a hands-off approach regarding identification procedures like showups and lineups, reasoning that juries or the triers of fact should determine if the process was reliable (Samaha, 2018, p. 369).
https://www.oyez.org/cases/1966/334
A lineup performed without the presence of Wade's lawyer after he was indicted violated his 6th Amendment right to counsel. In this case, Wade was entitled to counsel at the lineup. "The Court held that the identifications should not be excluded if they were based on observations other than the lineup" ("United States v. Wade." Oyez, www.oyez.org/cases/1966/334. Accessed 2 Nov. 2023.)
Was a sh0wup with Stoval in a hospital room after the victim underwent surgery, unduly suggestive, and did it violate Stoval's due process rights? Scotus ruled the showup was admissible but recognized that due process was a basis for challenging identification procedures on constitutional grounds (Samaha, 2018, p. 368).
https://www.oyez.org/cases/1966/223
In this case, SCOTUS allowed the admission of a handwriting exemplar but held that only a "per se" exclusionary rule could be an effective sanction to ensure law enforcement will respect the accused constitutional right to counsel at a critical lineup.
23 ABC News KERO story on eyewitness identification.
www.youtube.com/watch?v=E2edzFYx-Po
Eyewitness Misidentification - innocenceproject.org/eyewitness-misidentification/
Ronald Cotton - Eyewitness Identification - Getting it Right