In People v. Aranda (1965) 63 Cal.2d 518, the California Supreme Court adopted the following judicially declared rule of criminal procedure: "When the prosecution proposes to introduce into evidence an extrajudicial statement of one defendant that implicates a codefendant, the trial court must adopt one of the following procedures: (1) It can permit a joint trial if all parts of the extrajudicial statements implicating any codefendants can be and are effectively deleted without prejudice to the declarant. by effective deletions, we mean not only direct and indirect identifications of codefendants but any statements that could be employed against nondeclarant codefendants once their identity is otherwise established. (2) It can grant a severance of trials if the prosecution insists that it must use the extrajudicial statements and it appears that effective deletions cannot be made. (3) If the prosecution has successfully resisted a motion for severance and thereafter offers an extrajudicial statement implicating a codefendant, the trial court must exclude it if effective deletions are not possible." (Id. at pp. 530-531.) The United States Supreme Court soon held the rule had constitutional underpinnings. (Bruton v. United States (1968) 391 U.S. 123, 135-136.) In People v. Aranda (1965) the Supreme Court articulated a new rule. The court noted that the procedure then in effect had been criticized because it required jurors to perform a "'mental gymnastic'" that was impossible to perform. ( People v. Aranda, supra, 63 Cal.2d at p. 525.) The court said that practice was "unfair" and adopted a "judicially declared rule of practice." ( Id. at p. 530.) Henceforth, the court stated, if the prosecution proposes to introduce into evidence an extrajudicial statement of one defendant that implicates a codefendant, the court must either: (1) permit a joint trial "if all parts of the extrajudicial statements implicating any codefendants can be and are effectively deleted without prejudice to the declarant"; (2) sever the trials "if the prosecution insists that it must use the extrajudicial statements and it appears that effective deletions cannot be made," or; (3) permit a joint trial but exclude the extrajudicial statement if effective deletions cannot be made. ( Id. at pp. 530-531.)