What is the difference between a prior conviction for petty theft and sentence enhancements under section 666 of the California Penal Code?

And finally, there is a logical basis long recognized in the jurisprudence of this state to distinguish between a prior conviction which is a sentencing factor (as in section 666) and a prior conviction which is an element of a crime (as in section 12021). (People v. Bouzas, supra, 53 Cal.3d at p. 479, 279 Cal.Rptr. 847, 807 P.2d 1076.) "Numerous decisions note that when a prior conviction (or similar legal-status factor) is an element of a substantive offense, failure to require a jury determination on that element may improperly impair the People's ability to prove and secure legitimate convictions of these offenses. [Citation.]" (Ibid.)

The court explained that prosecutions for petty theft under Penal Code section 484, with sentence enhancements under section 666 "are indeed 'logically distinguishable' [citation] from the section 12021 situation described above. Although it is quite possible that a jury that does not hear evidence of ex-felon status in a section 12021 prosecution might 'rebel and exercise its "naked power" to acquit because [it] might not believe that possessing a concealable firearm should be criminal' ( [People v. Hall (1980) 28 Cal.3d 143] at p. 154 [167 Cal.Rptr. 844, 616 P.2d 826] ), a jury that is called on to decide whether a petty theft has been committed faces no similar 'logical' problem.... [A] jury need not know that the defendant has been incarcerated for a prior theft-related offense in order to decide the question before it, namely, whether the defendant has committed the essential elements of the substantive crime of petty theft. [Citation.]" (People v. Bouzas, supra, 53 Cal.3d at pp. 479-480, 279 Cal.Rptr. 847, 807 P.2d 1076.)