State v. Bly
In State v. Bly, 127 Ariz. 370, 621 P.2d 279 (1980), the Arizona Supreme Court held that neither double jeopardy nor double punishment considerations prevent the legislature from establishing a sentencing scheme such as Arizona's in which an element of a crime may also be used for sentence enhancement and aggravation.
Bly recognized that "the legislature's power to define crime and prescribe punishment" includes the power to dictate that a given circumstance constituting an element of an offense--there, the use of a handgun, which converted a robbery into armed robbery--may also afford the basis for both enhancing and aggravating the sentence imposed for that offense and for "making probation unavailable and a minimum prison term mandatory." Id. at 372, 373, 621 P.2d at 281, 282.