In what circumstances will a jury at the penalty phase of a capital trial be allowed to consider evidence of criminal propensity drawn from prior crimes?

In People v. Johnson (1993) 6 Cal.4th 1, 23 Cal.Rptr.2d 593, 859 P.2d 673, we held that the trial court at the penalty phase had no obligation to instruct the jury, without request, that it "should not use the `inference of criminal propensity drawn from proof of one incident of unadjudicated conduct as proof of the truth of the allegations of another such incident.'" (Id. at p. 49, 23 Cal.Rptr.2d 593, 859 P.2d 673.) We explained that a trial court, as a general rule, "owes no obligation to instruct on the limited purposes for which evidence of prior crimes is admissible." (Ibid.) We rejected the defendant's contention that this general rule should not apply to the penalty phase of a capital trial in light of the trial court's instruction "that (1) evidence of various specified criminal acts had been presented, (2) before the jury could use evidence of any such offense as an aggravating circumstance, it must find beyond a reasonable doubt that such offense occurred, and (3) except for such offenses, the jury `may not consider any evidence of any other criminal acts as an aggravating circumstance.'" (Id. at pp. 49-50, 23 Cal. Rptr.2d 593, 859 P.2d 673.)