In the case of California v. Green, the U.S. Supreme Court was asked to determine whether a preliminary hearing transcript and an out-of-court statement could be used as evidence in court when the witness refused to testify based on memory loss. The defendant, Marshall Green, had been convicted of robbery using these pieces of evidence after his victim claimed not to remember key details during trial due to fear for her safety. On appeal, Green argued that this violated his Sixth Amendment right "to be confronted with the witnesses against him." However, in a 6-2 decision announced in 1969, the Supreme Court upheld Green's conviction stating that both types of statements were admissible because they bore "indicia of reliability" - they were made under circumstances providing considerable assurance their truthfulness and reliability; thus did not violate confrontation clause rights if declarant is unavailable at trial but has given testimony at previous judicial proceedings which was subject to cross-examination.

In the dissenting opinion for California v. Green, Justice Harlan argued that the majority's decision to allow prior inconsistent statements as substantive evidence was a departure from traditional rules of evidence and could potentially infringe upon defendants' Sixth Amendment rights. He contended that such an approach would encourage prosecutors to use preliminary hearings as a means of preserving testimony rather than investigating probable cause. Furthermore, he expressed concern over potential abuses where witnesses might be coerced into giving false testimonies during these hearings due to lack of legal representation or understanding of their rights. Harlan also disagreed with the majority's interpretation of "testimonial" in relation to hearsay exceptions under Confrontation Clause jurisprudence, arguing it should only apply when there is cross-examination opportunity at trial itself not just at any point in proceedings.