specially concurring:
I
I join the court’s opinion except as to ■ Part III in which I concur in the judgment only. I agree that our decision in People v. Young, 814 P.2d 834 (Colo.1991), did not revive the 1986 death penalty statute. Young’s holding that certain provisions of the 1988 statute were facially invalid should not now preclude us from effectuating the severability clause of the death penalty statute. The severability clause, § 16-ll-103(8)(a), 8A C.R.S. (1986), provides that unconstitutional provisions of section 16-11-103 shall be severed and that the remaining provisions which can be given effect without the offending provisions shall be given effect. After Young, by virtue of the severability clause, there remained a sufficiently meaningful legislative enactment, see City of Lakewood v. Colfax Unlimited Ass’n, Inc., 634 P.2d 52, 70 (Colo.1981), namely, an authorized penalty of life imprisonment upon conviction for a class 1 felony.1 Because of the penalty of life imprisonment, no hiatus in the law punishing class 1 felonies was created by *208our holding in Young. Thus, the revival doctrine is inapplicable in this case.
II
Where I depart from the plurality is in its analysis of the defendant’s ex post facto claims.2 I agree, guided by the relevant reasoning in Dobbert v. Florida, 432 U.S. 282, 97 S.Ct. 2290, 53 L.Ed.2d 344 (1977), that the 1991 statute does not violate the ex post facto clauses of either the federal or state constitutions. However, we need not adopt for state constitutional purposes Dobbert’& other holdings which are immaterial to this case, much less the Supreme Court’s recent contraction of the scope of the federal ex post facto prohibition in Collins v. Youngblood, 497 U.S. 37, 110 S.Ct. 2715, 111 L.Ed.2d 30 (1990). In my view, the plurality’s wholesale acceptance of Dobbert and its uncritical invocation of Collins unnecessarily constricts the scope of our state constitution’s protections against ex post facto laws. Hence, I write separately.
A
The plurality, in Part III A, begins its analysis of the federal and state ex post facto claims by correctly acknowledging that even when specific clauses of our state constitution and our federal constitution are similarly or identically worded this court has found that our state constitutional clauses may afford greater protections to the citizens of Colorado than do their federal counterparts as construed by federal courts. See Young, 814 P.2d at 842. The plurality also correctly notes that we have found differences in wording between otherwise analogous clauses of the state and federal constitutions to warrant an interpretation of the state constitution which differs from that given the federal constitution by federal courts. See Bock v. Westminster Mall Co., 819 P.2d 55 (Colo. 1991). The plurality then notes that in our analysis in Young of the cruel and unusual punishment clause of our state constitution, we were attentive to the Supreme Court’s reasoning on the federal counterpart because both clauses are similarly worded. 814 P.2d at 845. I understand the plurality’s review of these approaches to mean only that there is no predetermined correspondence between textual similarity or difference and our interpretations of the state constitution which follow or depart from federal constitutional interpretation.
Thus, because the ex post facto clauses of our respective constitutions are similarly worded,3 we should be attentive to the Supreme Court’s interpretation of the federal ex post facto clause when we resolve claims brought under our state constitution’s prohibition of ex post facto laws. We have given the Supreme Court that attention in the past. See Garvey v. People, 6 Colo. 559 (1883). However, when the Supreme Court’s construction and application of the federal ex post facto clause departs in a significant way from its own precedents, especially from those precedents which we have found persuasive in our past constructions of the state ex post facto clause, then we must make a critical and independent assessment of the scope of our state constitution’s affirmative prohibitions. We are not committed to follow the Supreme Court when it abruptly changes course simply because we have followed it in the past. See Westminster Mall, 819 P.2d at 58 (declining to follow the “twists and turns” of federal First Amendment jurisprudence).
B
Unlike the plurality, I see no reason to embrace Collins v. Youngblood, 497 U.S. 37,110 S.Ct. 2715, 111 L.Ed.2d 30 (1990), as *209a matter of our state ex post facto jurisprudence, and several reasons not to. First, the Collins analysis is not necessary to resolve this case. Second, the Collins Court overruled two longstanding precedents, namely, Kring v. Missouri, 107 U.S. 221, 2 S.Ct. 443, 27 L.Ed. 506 (1883), and Thompson v. Utah, 170 U.S. 343, 18 S.Ct. 620, 42 L.Ed. 1061 (1898), both of which found ex post facto violations. This overruling is a clear indication that the Supreme Court has significantly diverged from its own precedents and should be a sign of caution to us. Third, both Kring and Thompson were precedents we have found persuasive and upon which we have relied in the development of ex post facto jurisprudence under our state constitutional clause. See Kolkman v. People, 89 Colo. 8, 300 P. 575, 584 (1931) (“[Tjhere may be procedural changes which ... otherwise affect the [accused] in such a harsh and arbitrary manner as to fall within the constitutional prohibition.”) (citing Kring); French v. Deane, 19 Colo. 504, 513, 36 P. 609 (1894) (also citing Kring). In my view, the Supreme Court’s jurisprudence in Collins leaves federal ex post facto law at the very least unsettled.4
When the plurality states that Collins “does little more than affirm the decision in Dobbert, which relied solely on the definition of an ex post facto law as set forth in Calder v. Bull, [3 U.S. (3 Dali.) 386,1 L.Ed. 648 (1798),]” plurality op. at 199, the plurality commits two fundamental errors. As I have demonstrated, Collins goes far beyond merely affirming Dobbert, and if it did nothing more “for our purposes,” plurality op. at 199, then Part III D of the plurality opinion is dicta. Thus, the plurality’s question, at 199, whether, under Collins, “the ex post facto clause of the Colorado Constitution still prohibits laws which affect ‘substantial protections’ or disadvantageously alter the situation of a party” (my emphasis), is speculation within dicta.
The other fundamental misstep in the plurality’s analysis is the view that Dob-bert relied solely on the definition of an ex post facto law as set forth in Calder, and that the “statutes at issue here can be tested under a Calder analysis.” Plurality op. at 199. In fact, Calder appears in Dobbert only once, and then only as a citation within a lengthy excerpt from another case, Lindsey v. Washington, 301 U.S. 397, 57 S.Ct. 797, 81 L.Ed. 1182 (1937). See Dobbert, 432 U.S. at 299, 97 S.Ct. at 2300. Rather, Dobbert explicitly relied on Beazell v. Ohio, 269 U.S. 167, 46 S.Ct. 68, 70 L.Ed. 216 (1925), which reformulated the Calder categories of those laws violative of the federal ex post facto clause. Dobbert, 432 U.S. at 292, 97 S.Ct. at 2297-98. See Collins, 497 U.S. at -, 110 S.Ct. at 2719.5
What Dobbert and this case have in common and what distinguishes them from Collins and other federal ex post facto cases is a judicial declaration of unconstitutionality with a subsequent legislative at*210tempt to statutorily fill the gap which would be created by the application of the void ab initio doctrine. In Dobbert, a case originating in Florida with a chronology of events similar to the case here, the Supreme Court was faced with several ex post facto claims, only one of which was explicitly predicated on the void ab initio doctrine. 432 U.S. at 297-98, 97 S.Ct. at 2300-01. Dobbert relied on Beazell only to answer one of those claims, a claim not premised on the void ab initio doctrine. That doctrine describes one possible state of affairs following a judicial invalidation of a statute, namely, that the statute was never in effect.6 Thus, the defendant in Dobbert argued that “there was no ‘valid’ death penalty in effect in Florida as of the date of his actions.” 432 U.S. at 297, 97 5.Ct. at 2300. In its analysis of the void ab initio claim, the Dobbert Court developed the concept of “operative fact” in order to diminish the conclusiveness of the void ab initio doctrine. The Court cited Chicot County Dist. v. Baxter State Bank, 308 U.S. 371, 374, 60 S.Ct. 317, 318-19, 84 L.Ed. 329 (1940), for the proposition that the broad statement in Norton v. Shelby Co.
as to the effect of a determination of unconstitutionality must be taken with qualifications. The actual existence of a statute, prior to such a determination, is an operative fact and may have consequences which cannot justly be ignored.
Dobbert, 432 U.S. at 297-98, 97 S.Ct. at 2300. The Dobbert Court thus extended the rule from the civil context of Chicot and stated that the existence of the penal statute served as an operative fact to warn the defendant of the penalty which the state would seek to impose should he be convicted of the crimes alleged. Id. The Court concluded that this “fair warning” was sufficiently compliant with the ex post facto clause of the federal constitution. Id.7
C
In Calder, Justice Chase set forth the now well-known categories of laws which violate the federal ex post facto clause:
1st. Every law that makes an action done before the passing of the law, and which was innocent when done, criminal; and punishes such action. 2d. Every law that aggravates a crime, or makes it greater than it was, when committed. 3d. Every law that changes the punishment, and inflicts a greater punishment than the law annexed to the crime, when committed. 4th. Every law that alters the legal rules of evidence, and receives less, or different, testimony, than the law required at the time of the commission of the offense, in order to convict the offender.
3 U.S. (3 Dali.) at 390. I note that in Collins, the Supreme Court characterized the Calder categories as implicating “the core concern of the Ex Post Facto Clause[ ].” 497 U.S. at-, 110 S.Ct. at 2719. I agree, but the fact that these are the core concerns does not mean that other categories of laws do not implicate the ex post facto clause. Thus, although I find the Calder categories seminal in the development of ex post facto law, both federal and state, the Calder categories are not exhaustive.
In response to a judicial invalidation of a penal statute, a legislature may decide to pass, as did the Florida legislature and the Colorado legislature here, a new penal stat*211ute not only correcting the constitutional infirmity but also providing that the penalties apply retrospectively. It is these new penal statutes, passed after a judicial invalidation, which constitute a category of laws not corresponding to any of the Calder categories. In Young, we invalidated certain provisions of the 1988 statute. Hence, according to the void ab initio doctrine, the law that can be said to be annexed to the crimes for purposes of the Calder analysis is problematical. It is problematical because, although there is no doubt that here the law annexed to the crimes when committed was the 1988 death penalty statute, it is equally clear that, but for the 1991 statutes, the law remaining after Young was decided, namely, the penalty of life imprisonment for a class 1 felony, is the law which would be applied by the court to the defendant’s alleged conduct at trial. Thus, concepts not explicitly found in the Calder catalog must be brought to bear to resolve an ex post facto challenge to this category of penal statutes. This is exactly what the Supreme Court did in Dobbert when it held that “the existence of the statute served as an ‘operative fact’ to warn the petitioner of the penalty which Florida would seek to impose on him if he were convicted of first-degree murder.” 432 U.S. at 298, 97 S.Ct. at 2300.
Invocation of this concept of “operative fact” in those cases which involve a judicial invalidation of a penal statute does not mean that the core Calder concerns are in any way diminished. The concept of an “operative fact” giving fair warning does not displace Calder at all. On the contrary, what we do take from Calder, even in a case which does implicate the void ab initio doctrine, is the importance of the time when the crimes were committed. For purposes of ex post facto analysis, the 2d, 3d and 4th Calder categories all refer to the time when the alleged offense was committed.8 The law “annexed to the crime[s],” Calder (3rd category), allegedly committed by Allen Thomas, Jr. was the 1988 death penalty statute.
With the law annexed to Thomas’s alleged crimes being the 1988 statute, two related issues are raised. First, what is the effect of Young’s invalidation of certain provisions of the 1988 statute on the law annexed to the defendant’s alleged crimes? Second, does the retroactive application of the October 1991 statutes violate the state constitution’s prohibition of ex post facto laws? In my view, these issues are intertwined and the resolution of the first must be made with an eye toward the resolution of the second.
Although it is clear that, but for the 1991 statutes, the law remaining after Young was decided is the law which would be applied by the court to the defendant’s conduct at trial, it is also clear that the General Assembly never intended a hiatus in the availability of the death penalty for the punishment of first degree murder. From this perspective, the void ab initio doctrine is less than absolute. From Dob-bert, I gather that a judicial determination of unconstitutionality may not necessarily cancel the existence of fair warning to all that the state will seek to impose the death penalty for certain crimes. The death penalty per se is not unconstitutional in Colorado. People v. Davis, 794 P.2d 159 (Colo. 1990). When the defendant allegedly committed the murder, the death penalty was a possible punishment for first degree murder and the defendant here was on notice of that fact. In my view, the death penalty provision of the 1988 statute was an operative fact serving to give fair warning to the defendant here. The retrospectivity of the 1991 statute thus is not absolute. Because the defendant was on notice that the death penalty was an available punishment for murder, passage of the retroactive 1991 statutes does not violate the ex post facto prohibition of the state constitution.9
Thus, I depart from the plurality’s view that we can be guided solely “by the histor*212ical Calder test for an ex post facto law.” Plurality Op. at 199. Also, just because Dobbert provided the proper resolution of the void ab initio problem does not mean that we must embrace other holdings immaterial to the case here, e.g., that “[e]ven though it may work to the disadvantage of a defendant, a procedural change is not ex post facto.” 432 U.S. at 293, 97 S.Ct. at 2298 (a holding cited by the plurality at 195). A fortiori, we need not embrace the holdings in Collins, a case which did not implicate the void ab initio problem.
In my view, applying the concept of an “operative fact” which gives fair warning in cases implicating the void ab initio problem need not depreciate the “substantial protections” or “substantial disadvantage” tests developed in earlier federal ex post facto cases and followed in our case law. The case before us does not require us to conclude that the scope of the state constitution’s prohibition of ex post facto laws does not include those laws which retroactively disadvantage an accused. In People v. Billips, 652 P.2d 1060 (Colo.1982), for example, we held that “[t]wo critical elements must be present for a criminal statute to be stricken down as an ex post facto law: ‘it must be retrospective ... and it must disadvantage the offender affected by it.’ ” 652 P.2d at 1064 (citing Weaver v. Graham, 450 U.S. 24, 29, 101 S.Ct. 960, 964, 67 L.Ed.2d 17 (1981)). The standard requires both retrospectivity and a disadvantage to the accused. This means that a statute may be retrospective and not there-' by violate the ex post facto clause if it does not disadvantage the defendant. Simply put, an actor is not disadvantaged if he was on fair notice of both the punishment which the People would seek to impose on his conduct and the procedures to be employed in imposing that punishment.
D
The issues then are whether the central provisions of the 1991 statutes disadvantage the defendant here. These issues too should be handled under the “operative fact” concept developed to overcome the absoluteness of the void ab initio doctrine. In Dobbert, the Supreme Court resolved the several ex post facto claims there by resort to what it conceived as different and independent bases. 432 U.S. at 292 n. 6, 97 S.Ct. at 2298 n. 6 (procedural changes and ameliorative changes). Those analytical distinctions may have been compelled by the facts there. Here we need not consider whether a change in the law is procedural or substantive. If the defendant was on notice of what the state would have sought to do, whether substantively or procedurally, at the time of his actions, then there is no ex post facto violation provided that what the state seeks retrospectively to do is equally or less burdensome than what it could have sought to do at that time. Thus, rather than tangle with the substance versus procedure distinction, we should inquire whether the law annexed to the crimes when committed, notice of which is an operative fact, was as, or less, burdensome than the new retrospective law to be applied at trial.
With the reinstatement of the four-step jury verdict by the 1991 statutes, the procedure for imposing the death penalty was not made more onerous than the jury verdict procedure which was annexed to the crimes when the crimes were committed. Thus, the defendant was on notice when the crimes were committed of the procedures provided by the retrospective statutes. Likewise, the change in the parole possibilities for a life sentence made by the 1991 statutes do not disadvantage the defendant because the defendant was on notice of a more burdensome parole scheme at the time he allegedly committed the crimes. The defendant’s speculation that the jury will deliberate differently and to his disadvantage because of the new parole scheme does not defeat his being on notice that the state intended to impose the death penalty and/or a life sentence with harsher parole requirements. The defendant therefore is not disadvantaged by the retroactive statutes in this regard. Finally, the statutory changes in the aggravators are not more burdensome to the defendant, as I agree with the plurality that the statutory terms must be defined according to our decision in Davis.
*213III
For the reasons expressed above, I join in Parts II and IV of the court’s opinion, and I concur in the judgment reached in Part III.
. That life imprisonment upon conviction of a class 1 felony is sufficiently meaningful is indicated by section 16-ll-103(8)(b), 8A C.R.S. (1986) (providing for life imprisonment should a particular death sentence be held invalid).
. The People in fact bring this appeal from the ruling by the trial court which found that the 1991 statutes violate the ex post facto clause.
. The plurality states that "[t]here is one notable textual difference” between those clauses, namely, the inclusion of the prohibition of laws “retrospective in [their] operation.” Plurality op. at 192. The retrospectivity clause, however, is separate from, not an appendage to, the ex post facto clause. See French v. Dean, 19 Colo. 504, 36 P. 609 (1894); Denver, South Park & Pacific Ry. Co. v. Woodward, 4 Colo. 162 (1878).
. Although Collins expressly overruled only Kring and Thompson, it is unclear whether Collins does not undermine other cases as well, particularly cases decided in the interim between Dobbert and Collins. See Weaver v. Graham, 450 U.S. 24, 29, n. 12, 101 S.Ct. 960, 964, n. 12, 67 L.Ed.2d 17 (1981) ("our decisions prescribe that two critical elements must be present for a criminal or penal law to be ex post facto: it must be retrospective, that is, it must apply to events occurring before its enactment, and it must disadvantage the offender affected by it.”) (citing Thompson for the proposition that ”[a]l-teration of a substantial right ... is not merely procedural, even if the statute takes a seemingly procedural form.”) (also citing Kring) (notes omitted); and Miller v. Florida, 482 U.S. 423, 430, 107 S.Ct. 2446, 2451, 96 L.Ed.2d 351 (1987) (citing the foregoing Weaver test approvingly). Indeed, Dobbert itself relies on Lindsey v. Washington, 301 U.S. 397, 57 S.Ct. 797, 81 L.Ed. 1182 (1937), which cited both Kring and Thompson approvingly. 432 U.S. at 299, 97 S.Ct. at 2300.
. The Beazell formulation omitted the 4th Calder category, which includes "[e]very law that alters the legal rules of evidence, and receives less, or different, testimony, than the law required at the time of the commission of the offense.” 3 U.S. (3 Dali.) at 390. Cf. Hopt v. Utah, 110 U.S. 574, 4 S.Ct. 202, 28 L.Ed. 262 (1884), and Thompson v. Missouri, 171 U.S. 380, 18 S.Ct. 922, 43 L.Ed. 204 (1898), discussed in Dobbert, 432 U.S. at 293, 97 S.Ct. at 2298. Thus, it also is unclear whether Collins really reestablished Calder as the dispositive case for federal ex post facto analyses, 497 U.S. at-, 110 S.Ct. at 2721 (“[T]he prohibition which may not be ' evaded is the one defined by the Calder categories.”).
. The void ab initio doctrine received its classic formulation in Norton v. Shelby Co.: "An unconstitutional act is not a law; it confers no rights; it imposes no duties; it affords no protection, it creates no office; it is, in legal contemplation, as inoperative as though it had never been passed.” 118 U.S. 425, 442, 6 S.Ct. 1121, 1125, 30 L.Ed. 178 (1886). See also Ex parte Siebold, 100 U.S. 371, 376-77, 25 L.Ed. 717 (1879) ("An unconstitutional law is void, and is as no law. An offence created by it is not a crime. A conviction under it is not merely erroneous, but is illegal and void, and cannot be a legal cause of imprisonment.”).
. The void ab initio doctrine was not implicated in Lindsey v. Washington, 301 U.S. 397, 57 S.Ct. 797, 81 L.Ed. 1182 (1937), cited by the Dobbert dissenters for the proposition that although there the defendant had notice of a possible punishment, the retrospective change in the law making the punishment mandatory nevertheless violated the ex post facto clause. Further, notice of a possible punishment is not notice of a mandatory punishment.
. The first category is inapplicable since the alleged conduct of the defendant was not innocent when done.
. I agree with the plurality that our decisions in People v. Tenneson, 788 P.2d 786 (Colo.1990), and People v. O'Neill, 803 P.2d 164 (Colo.1990), did not defeat notice of the death penalty.