In United States v. Owens, 484 U.S. 554 (1988), the Court addressed the issue of whether a witness's lack of memory regarding the basis of a prior statement posed a Confrontation Clause problem when the witness testified at trial and was subject to cross-examination. See id. at 555-56, 108 S. Ct. at 840. The declarant in Owens was a corrections officer who experienced memory loss as a result of an attack by the defendant. Id. at 556, 108 S. Ct. at 840-41. At trial, the officer stated he could not remember seeing the defendant attack him, but testified that he could remember identifying the defendant in an interview after the attack. Id. The officer also had difficulty remembering his hospitalization after the attack. Id. The Court held that there was no Confrontation Clause violation because the defendant had the opportunity to, and did, cross-examine the officer. Id. at 559-60, 108 S. Ct. at 842-43. The court agreed with Justice Harlan's concurrence in California v. Green (1970), explaining: "'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."' ." (Owens, at p. 559.) "It is sufficient," the court continued, "that the defendant has the opportunity to bring out such matters as the witness' bias, his lack of care and attentiveness, his poor eyesight, and even (what is often a prime objective of cross-examination, the very fact that he has a bad memory." (Ibid.) Although the "weapons available to impugn the witness' statement when memory loss is asserted will of course not always achieve success," the court concluded that "successful cross-examination is not the constitutional guarantee." (Id. at p. 560.) "Ordinarily a witness is regarded as 'subject to cross-examination' when he is placed on the stand, under oath, and responds willingly to questions." (Id. at p. 561.) The U.S. Supreme Court granted certiorari specifically "to resolve the conflict with other Circuits on the significance of a hearsay declarant's memory loss both with respect to the Confrontation Clause and with respect to Rule 802." The Supreme Court spoke directly on the issue of whether a declarant who is "unavailable" for the purposes of the Federal Rules of Evidence ("FRE") 804(a)(3), could be available to satisfy the Confrontation Clause of the Constitution. Id. at 563-64. As the Court observes: "Respondent argues that this reading is impermissible because it creates an internal inconsistency in the Rules, since the forgetful witness who is deemed "subject to cross-examination" under 801(d)(1)(C) is simultaneously deemed "unavailable" under 804(a)(3). . . . It seems to us, however, that this is not a substantive inconsistency, but only a semantic oddity resulting from the fact that Rule 804(a) has for convenience of reference in Rule 804(b) chosen to describe the circumstances necessary in order to admit certain categories of hearsay testimony under the rubric "Unavailability as a witness." . . . It would seem strange, for example, to assert that a witness can avoid introduction of testimony from a prior proceeding that is inconsistent with his trial testimony, by simply asserting lack of memory of the facts to which the prior testimony related. But that situation, like this one, presents the verbal curiosity that the witness is "subject to cross-examination" under Rule 801 while at the same time "unavailable" under Rule 804(a)(3). Quite obviously, the two characterizations are made for two entirely different purposes and there is no requirement or expectation that they should coincide." (Owens, 484 U.S. at 563-64.) Owen allows the possibility that memory loss of declarant testifying at trial can be so severe that admitting such testimony could violate the Confrontation Clause. 484 U.S. at 557-58 & n.2. Owen hints that if the Court were to decide the issue, memory loss would not violate the Confrontation Clause as long as declarant willingly testify under oath and was subject to cross-examination. Id. at 557-58 & n.2.