In California v. Green (1970) 399 U.S. 149, witness Porter, in a statement to police, implicated defendant Green as Porter's supplier of marijuana. At Green's preliminary hearing, Porter, then subject to cross-examination by Green's attorney, again identified Green as Porter's supplier of marijuana. At trial however, Porter became nonresponsive; he indicated that he was unable to remember events and, because he was on LSD at the time he obtained the marijuana, he was uncertain as to how he got it. After addressing the issue of whether admitting Porter's preliminary hearing testimony violated Green's confrontation rights, the court turned to "a narrow question lurking in this case concerning the admissibility of Porter's statements to Officer Wade." The question arose because "Porter claimed at trial that he could not remember the events that occurred after Green telephoned him and hence failed to give any current version of the more important events described in his earlier statement." (California v. Green, supra, at p. 168.) Nevertheless, the court declined to resolve the issue, stating, "whether Porter's apparent lapse of memory so affected Green's right to cross-examine as to make a critical difference in the application of the Confrontation Clause in this case is an issue which is not ripe for decision at this juncture." (Id. at pp. 168-169.) In his concurring opinion, Justice Harlan stated, "There is no 'confrontation' reason why the prosecution should not use a witness' prior inconsistent statement for the truth of the matters therein asserted. Here the prosecution has produced its witness, Porter, and made him available for trial confrontation. That, in my judgment, perforce satisfies the Sixth Amendment. . . .The fact that the witness, though physically available, cannot recall either the underlying events that are the subject of an extra-judicial statement or previous testimony or recollect the circumstances under which the statement was given, does not have Sixth Amendment consequence. The prosecution has no less fulfilled its obligation simply because a witness has a lapse of memory. The witness is, in my view, available. To the extent that the witness is, in a practical sense, unavailable for cross-examination on the relevant facts, . . . confrontation is nonetheless satisfied." (Id. at pp. 188-189 (conc. opn. of Harlan, J.).) In Owens, the court addressed the issue the majority in California v. Green, supra, left unresolved; specifically, whether the confrontation clause "bars testimony concerning a prior, out-of-court identification when the identifying witness is unable, because of memory loss, to explain the basis for the identification." (Owens, supra, 484 U.S. at pp. 555-556.) The court stated that it "agreed with the answer suggested 18 years ago by Justice Harlan: 'The Confrontation Clause guarantees only "an opportunity for effective cross-examination, not cross-examination that is effective in whatever way, and to whatever extent, the defense might wish."'" (Id. at p. 559.)