Does the term "substantial" in the definition of an aggravating circumstance in a murder case apply to determine whether the accused has a history of serious assaultive criminal convictions?

14 In support of his contention that the term "substantial" is unconstitutionally vague, defendant cites a Georgia capital case in which the word "substantial" was used as part of an aggravating circumstance, i.e., whether the murder is committed by a person who has a "substantial history of serious assaultive criminal convictions." The Georgia court found the word "highly subjective" and the aggravating circumstance unconstitutionally vague. (Arnold v. State (1976) 236 Ga. 534, 224 S.E.2d 386.) The differences between the Georgia case and this case are obvious.