SNEED, Circuit Judge:
Appellants are a class of Arizona prisoners sentenced to death. They attack their death sentences on the ground that the Arizona law under which they were sentenced, as interpreted by the Arizona Supreme Court, is unconstitutional. They further claim that even if it is constitutional, its application to them violates the ex post facto and double jeopardy clauses of the Constitution, and that their constitutional rights to speedy sentences were violated. The district court rejected these contentions and upheld the death sentences. We affirm.
I.
FACTS AND BACKGROUND
In 1973 the Arizona legislature adopted alternative penalties for first degree murder of death or life imprisonment without possibility of parole for 25 years. Ariz.Rev. Stat. § 13-454 (1978) (current version at Ariz.Rev.Stat. § 13-703). The enactment required the judge to hold a presentence hearing at which he would hear evidence of aggravating and mitigating circumstances. After considering the evidence presented at the presentence hearing, and weighing it together with evidence relevant to aggravation or mitigation introduced at trial, the judge was required to make a finding as to the existence or non-existence of each aggravating and mitigating circumstance listed in the statute. In order to impose the death penalty, the judge was required to find the existence of one or more of the aggravating circumstances listed in the statute and “that there are no mitigating circumstances sufficiently substantial to call for leniency.” Ariz.Rev.Stat. § 13-454(D) (1978) (current version at Ariz.Rev. Stat. § 13-703(E)).
In upholding section 13-454 against a challenge for vagueness, the Arizona Supreme Court in 1976 interpreted the list of mitigating factors in that section to be exclusive. State v. Richmond, 114 Ariz. 186, 560 P.2d 41 (1976), cert. denied, 433 U.S. 915, 97 S.Ct. 2988, 53 L.Ed.2d 1101 (1977). This restrictive interpretation was reaffirmed on March 1, 1978, in State v. Bishop, 118 Ariz. 263, 576 P.2d 122 (1978), sentence vacated sub nom. Bishop v. Arizona, 439 U.S. 810, 99 S.Ct. 69, 58 L.Ed.2d 103 (1978) (death sentence vacated and remanded for reconsideration in light of Lockett v. Ohio, 438 U.S. 586, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978)), sentence reinstated, State v. Bishop, 127 Ariz. 531, 622 P.2d 478 (1980).
On April 21,1978, two death-row inmates petitioned the district court for writs of habeas corpus, alleging the unconstitutionality of section 13-454 as interpreted in [1257]*1257State v. Richmond and State v. Bishop. The district court enjoined the state from putting the two petitioners to death, concluding that the failure of section 13-454, as interpreted, to permit consideration of all relevant mitigating circumstances violated petitioners’ rights under the Eighth and Fourteenth Amendments of the United States Constitution. Richmond v. Cardwell, 450 F.Supp. 519 (D.Ariz.1978).
On May 2, 1978, the Arizona Supreme Court directed the execution of John Henry Knapp. Knapp immediately instituted the present action in district court, alleging that the court’s reasoning in Richmond v. Cardwell was applicable to all inmates on Arizona’s death row. The district court, on May 12, 1978, enjoined the state from imposing the death penalty on any state prisoners. On July 3, 1978, the United States Supreme Court found an Ohio death penalty statute unconstitutional because it limited consideration of mitigating factors to those enumerated in the statute and thereby potentially excluded consideration of relevant mitigating factors. Lockett v. Ohio, 438 U.S. 586, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978); see also Bell v. Ohio, 438 U.S. 637, 98 S.Ct. 2977, 57 L.Ed.2d 1010 (1978).
The Arizona Supreme Court reacted to the Lockett decision by deciding in State v. Watson, 120 Ariz. 441, 586 P.2d 1253 (1978), cert. denied, 440 U.S. 924, 99 S.Ct. 1254, 59 L.Ed.2d 478 (1979), that section 13-454 was unconstitutional insofar as it limited the right of the defendant to show additional mitigating circumstances. 120 Ariz. at 445, 586 P.2d at 1257. The Watson court then reasoned that the offending portion was “severable” and could be “deleted,” and proceeded to do so, stating that if the state legislature had been aware of the constitutional problems, it would have permitted consideration of all mitigating factors.1 The result of Watson was to change the Arizona procedure for imposing the death penalty to require that the judge hear and consider evidence relevant to any mitigating circumstances and otherwise to leave the procedure intact.
On May 1, 1979, the Arizona legislature adopted the present version of Ariz.Rev. Stat. § 13-703 which, in essence, codiified the result reached in Watson.2
II.
DISTRICT COURT DECISION
In July 1979 the district court in this case ordered that there be no executions in Arizona until the state moved to dissolve the May 12,1978, injunction barring executions. The state made such a motion on January 9, 1980, on the basis that the inmates had been or would be sentenced under a procedure that permits consideration of all mitigating circumstances. The district court, on April 18, 1980, vacated its original injunction and then reimposed a stay of all executions pending appeal to this court. Knapp v. Cardwell, 513 F.Supp. 4 (D.Ariz.1980). In a thorough and well-reasoned opinion, the court held that the post- Watson version of section 13-454 was neither void for vagueness nor violative of the Eighth and Fourteenth Amendments. The court also noted its limited power to review state court interpretations of state statutes, and held that in any event the Arizona Supreme Court’s interpretation of the statute in Watson was reasonable. The district court went on to reject the prisoners’ claims that the application of Watson to them violated the double jeopardy and ex post facto clauses of the Constitution, and held that it was not appropriate to consider the prisoners’ claims of violation of their right to speedy sentencing in a class action. We agree with the district court.
[1258]*1258III.
ISSUES ON APPEAL
Appellants3 vigorously attack the decision of the district court. They assert both that the result in State v. Watson renders section 13-454 void for vagueness, and that the procedure used by the court to reach its result usurped the powers of the Arizona Legislature and thus violated the Fourteenth Amendment and the guarantee clause of the United States Constitution. They next urge that even if the Watson court reached a permissible result, its application to them violates the double jeopardy and ex post facto clauses of the Constitution. Finally, they continue to insist that delays in imposing sentence on them have violated their Sixth Amendment right to speedy sentencing. We shall address each of these issues.
IV.
THE VAGUENESS ISSUE
The Arizona Supreme Court in Watson maintained that it was “severing” the un[1259]*1259constitutional from the constitutional portions of Ariz.Rev.Stat. § 13-454. State v. Watson, 120 Ariz. at 445, 586 P.2d at 1257. Appellant prisoners argue that by claiming to have effected a severance, the Watson court must have deleted all of subsection F, the subsection that lists the mitigating factors. It follows, they argue, that the remainder of the statute is left with meaningless internal references to a non-existent subsection F and thus is void for vagueness. Alternatively, appellants contend that the deletion of subsection F leaves the statute without any authorization for consideration of mitigating factors, with the consequence that it violates the Eighth and Fourteenth Amendments.
The district court held that Watson merely reinterpreted section 13-454 to allow consideration of any mitigating factors, and did not “sever” any particular language. Knapp v. Cardwell, 513 F.Supp. at 11. While the use of the word “severance” is troublesome, the unmistakable effect of the Watson decision as a whole is to reinterpret the statute to allow any mitigating factor to be considered.
The intent of the Watson court is clear. The court did not state that subsection F in its entirety was unconstitutional. It merely invalidated a prior interpretation of that provision “insofar as it limits the right of the defendant to show additional circumstances.” State v. Watson, 120 Ariz. at 445, 586 P.2d at 1257 (emphasis added). The failure of the court explicitly to overrule State v. Richmond, 114 Ariz. 186, 560 P.2d 41 (1976), cert. denied, 433 U.S. 915, 97 S.Ct. 2988, 53 L.Ed.2d 1101 (1977), the case in which the Arizona Supreme Court held the list of mitigating factors to be exclusive, is not determinative. The intent and effect of the Watson decision are clear.
We agree with the district court that the substance of Watson was merely the elimination of the restriction on cognizable mitigating circumstances engrafted onto the statute by State v. Richmond. This constitutes a reinterpretation, and it has long been within the prerogative of the highest state court to interpret, or reinterpret, state statutes. See Wainwright v. Stone, 414 U.S. 21, 94 S.Ct. 190, 38 L.Ed.2d 179 (1973); Garner v. Louisiana, 368 U.S. 157, 82 S.Ct. 248, 7 L.Ed.2d 207 (1961); Smiley v. Kansas, 196 U.S. 447, 455, 25 S.Ct. 289, 290, 49 L.Ed. 546 (1905).
That the Arizona Supreme Court did not intend to delete the entire subsection F from the statute is further supported by its opinions written after Watson wherein the court specifically cites to subsection F. See State v. Jordan, 126 Ariz. 283, 614 P.2d 825, cert. denied, 449 U.S. 986, 101 S.Ct. 408, 66 L.Ed.2d 251 (1980); State v. Steelman, 126 Ariz. 19, 612 P.2d 475, cert. denied, 449 U.S. 913, 101 S.Ct. 287, 66 L.Ed.2d 141 (1980); State v. Brookover, 124 Ariz. 38, 601 P.2d 1322 (1979). In the Jordan and Steelman cases, the court actually quoted language from subsection F.
Since we have found that subsection F was not deleted from Ariz.Rev.Stat. § 13-454 by the Arizona Supreme Court in Watson, we hold that the post- Watson version of the statute is not void for vagueness. We further hold that the post- Watson version of section 13 — 454 allows consideration of all mitigating factors and thus does not violate the Eighth and Fourteenth Amendments.
V.
THE USURPATION ISSUE
Appellant prisoners argue that, even assuming the Arizona Supreme Court intended in Watson to accomplish what we have found they did, the effect of the decision constitutes judicial legislation to create criminal penalties in violation of the Fourteenth Amendment due process clause and the Article IV, section 4, guarantee of a republican form of government for the states. We do not agree.
To support their argument, appellants employ alternative approaches. They assert, first, that in light of the legislative history and wording of Ariz.Rev.Stat. § 13-454, there is no permissible way to interpret it to allow a court to consider all mitigating circumstances, and therefore only a legisla[1260]*1260tive amendment could cure it. In the alternative, appellants posit that even if the Arizona Supreme Court could have reached its interpretation of section 13-454 by some permissible means, it instead attempted to achieve that end by a “severance,” which in this case requires the addition of language to the statute, and that can be done only by the legislature. In either case, appellants claim that the Arizona Supreme Court’s attempt in Watson to conform section 13-454 to constitutional requirements usurped the function of the state legislature and was thus invalid.
A. The State Court’s Interpretation Is Not Within the Scope of Federal Review
Normally the construction of a state statute by the highest court of that state must be treated as if it had been incorporated into the words of the statute. Poulos v. New Hampshire, 345 U.S. 395, 402, 73 S.Ct. 760, 764, 97 L.Ed. 1105 (1953). State courts have the final authority to interpret and, where they see fit, to reinterpret that state’s legislation. Garner v. Louisiana, 368 U.S. 157, 82 S.Ct. 248, 7 L.Ed.2d 207 (1961). See also, Wainwright v. Stone, 414 U.S. 21, 22-23, 94 S.Ct. 190, 192-193, 38 L.Ed.2d 179 (1973); N.A.A.C.P. v. Button, 371 U.S. 415, 432 (1963); Winters v. New York, 333 U.S. 507, 514, 68 S.Ct. 665, 669, 92 L.Ed. 840 (1948).
The Supreme Court has established that courts should construe legislation in a constitutional manner “if fairly possible,” Crowell v. Benson, 285 U.S. 22, 62, 52 S.Ct. 285, 296, 76 L.Ed. 598 (1932); see also Broadrick v. Oklahoma, 413 U.S. 601, 613, 93 S.Ct. 2908, 2916, 37 L.Ed.2d 830 (1973), and that state courts can use statutory interpretation to validate otherwise questionable death penalty statutes. See Proffitt v. Florida, 428 U.S. 242, 96 S.Ct. 2960, 49 L.Ed.2d 913 (1976); also see discussion in Knapp v. Cardwell, 513 F.Supp. at 11 n.12. Federal courts will not review a state supreme court’s interpretation of its own statute unless that interpretation is clearly untenable and amounts to a subterfuge to avoid federal review of a deprivation by the state of rights guaranteed by the Constitution. See Mullaney v. Wilbur, 421 U.S. 684, 691 n.11, 95 S.Ct. 1881, 1885 n.11, 44 L.Ed.2d 508 (1975); Radio Station WOW, Inc. v. Johnson, 326 U.S. 120, 129, 65 S.Ct. 1475, 1480, 89 L.Ed. 2092 (1945); Ward v. Love County, 253 U.S. 17, 40 S.Ct. 419, 64 L.Ed. 751 (1920); Terre Haute & I. R. Co. v. Indiana, 194 U.S. 579, 24 S.Ct. 767, 48 L.Ed. 1124 (1904).
B. The Arizona Supreme Court’s Interpretation of the Statute in Watson is not Untenable
Appellants argue that review is necessary and proper here because the Arizona Supreme Court’s interpretation of section 13-454 is clearly incompatible with the language of section 13-454 and its legislative history.
We agree with the district court that the Watson construction of the statute is not untenable. Knapp v. Cardwell, 513 F.Supp. at 12-13. The only positive command of section 13-454(F) is that the court shall consider the mitigating factors listed there. Its language nowhere dictates that the court shall consider no other mitigating factors, nor does the language of subsection D preclude use of unlisted factors in deciding whether any mitigating circumstances are “sufficiently substantial to call for leniency.” Ariz.Rev.Stat. § 13-454(D).4 Moreover, the fact that a bill introduced in the House of Representatives of Arizona, containing an explicit provision for open mitigation, was defeated in favor of a Senate bill containing no such explicit language on open mitigation, does not compel a finding that the legislature intended the list of mitigating factors to be exclusive. See dis[1261]*1261cussion in Knapp v. Cardwell, 513 F.Supp. at 12-13 n.15.
C. The Arizona Supreme Court in Watson was not Legislating
We agree with the district court that the Arizona Supreme Court in Watson was merely reinterpreting Ariz.Rev.Stat. § 13-454. Arizona law adjures that statutes should be construed to effect their objects, and that interpretations that imperil the constitutionality of statutes be avoided when reasonably possible. Ariz. Rev.Stat. §§ 1-211, et. seq.5 The court in Watson was being guided by this precept. The language of the statute remained precisely what it had been since it was first enacted. If anything was “severed” by Watson, it was the gloss imparted to the statute (erroneously we now know) by Richmond. We see no difference between such a “severance” in correction of earlier judicial error and an overruling or reinterpretation.
We also agree with the district court that the Watson result was not precluded by the Watson court’s refusal to repudiate State v. Richmond. See discussion in 513 F.Supp. at 13-14. No matter how the court may have characterized it, what it did in Watson was to undo what it had done earlier in Richmond.
Our conclusion regarding the Watson interpretation of section 13-454 means that the Arizona Supreme Court did not impose a penalty unauthorized by the legislature in violation of the Eighth and Fourteenth Amendments. At all relevant times, Arizona had on its books a statute that clearly authorized death as a punishment for the crimes each of the appellants committed. The United States Supreme Court’s decision in Lockett v. Ohio, 438 U.S. 586, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978), which declared unconstitutional an Ohio death penalty statute that expressly limited the mitigating factors the sentencing court could consider, did not render the Arizona death penalty a nullity. It merely made sentences rendered under its then current construction unenforceable. See In re Graham, 138 U.S. 461, 11 S.Ct. 363, 34 L.Ed. 1051 (1891). This left it open to the Arizona Supreme Court to reinterpret section 13-454 to conform to the constitutional mandate or to adhere to its original interpretation and invoke the provision for a life sentence. See Garner v. Louisiana, 368 U.S. 157, 82 S.Ct. 248, 7 L.Ed.2d 207 (1961). It chose to reinterpret section 13-454. The Constitution does not preclude that choice. See Smiley v. Kansas, 196 U.S. 447, 455, 25 S.Ct. 289, 290, 49 L.Ed. 546 (1904).6
The choice made by the Arizona Supreme Court between competing interpretations of the statute was not a legislative act. Unlike legislative choice, the selection by a court between competing interpretations is circumscribed by legislative intent which, while not known precisely with respect to all possible issues, does eliminate a wide range of choices that would otherwise be available. Moreover, judicial choice can only exist as the result of a highly structured adversarial process instituted not by judges but by the adversaries themselves. And most importantly, the court’s choice of competing interpretations, in the absence of constitutional constraints, can be overturned by the legislature. These differences justify our rejection of the charge of usurpation, and so it follows that we also must reject the related due process and guarantee clause arguments.7
[1262]*1262VI.
THE EX POST FACTO ISSUE
It has been said that the ex post facto clause prohibits:
any statute which punishes as a crime an act previously committed, which was innocent when done; which makes more burdensome the punishment for a crime, after its commission, or which deprives one charged with crime of any defense available according to law at the time when the act was committed. . . .
Beazell v. Ohio, 269 U.S. 167, 169, 46 S.Ct. 68, 70 L.Ed. 216 (1925) (emphasis added). Although the ex post facto prohibition, United States Constitution, art. I, § 10, el. 1, literally applies only to legislative acts, the Supreme Court has incorporated the principle upon which the prohibition rests into the due process clauses of the Fifth and Fourteenth Amendments. See Marks v. United States, 430 U.S. 188, 191-92, 97 S.Ct. 990, 992-93, 51 L.Ed.2d 260 (1977); Bouie v. City of Columbia, 378 U.S. 347, 84 S.Ct. 1697, 12 L.Ed.2d 894 (1964).
The first of appellant’s two ex post facto arguments is that, because section 13-454 as interpreted in Richmond v. Cardwell, 450 F.Supp. 519 (D.Ariz.1978) was unconstitutional (per Lockett v. Ohio, 438 U.S. 586, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978)), Arizona had no death penalty prior to Watson. Watson, therefore, was a judicial enlargement of the punishment for appellants’ crimes committed before that decision in violation of the ex post facto clause.
We agree with the district court that Dobbert v. Florida, 432 U.S. 282, 97 S.Ct. 2290, 53 L.Ed.2d 344 (1977), requires rejection of this argument. Dobbert committed his crime when Florida had an applicable death penalty statute of a type later declared unconstitutional in Furman v. Georgia, 408 U.S. 238, 92 S.Ct. 2726, 33 L.Ed.2d 346 (1972). Prior to Dobbert’s trial, Florida passed a new death penalty statute to conform to the new constitutional requirements as defined in Furman v. Georgia. Dobbert was tried and sentenced under the new statute, which was found constitutional in Proffitt v. Florida, 428 U.S. 242, 96 S.Ct. 2960, 49 L.Ed.2d 913 (1976).
Dobbert argued that, because the type of Florida death statute in effect when he committed his crime was later found to be unconstitutional, Florida had no valid death penalty at the time of his crime. Therefore, his trial and sentencing under the new law resulted in an ex post facto enlargement of the penalty for his crime subsequent to the time of its commission. The Supreme Court in Dobbert rejected the notion that constitutional invalidation of the former Florida death penalty statute rendered it a nullity. 432 U.S. at 297, 97 S.Ct. at 2300. See Chicot County Drainage District v. Baxter State Bank, 308 U.S. 371, 374, 60 S.Ct. 317, 318, 84 L.Ed. 329 (1940). Instead, the Court found that the statute was an “operative fact” that gave defendant fair notice of the penalty — death—that Florida would seek to exact for his crime. Dobbert v. Florida, 432 U.S. at 298, 97 S.Ct. at 2300. This notice provided compliance with the ex post facto provision of the United States Constitution. 432 U.S. at 298, 97 S.Ct. at 2300. The Arizona law prior to Watson here performed the same function. See State v. Smith, 125 Ariz. 412, 610 P.2d 46 (1980).8
Some of the appellants attempt to distinguish Dobbert on the ground that Dobbert was tried and sentenced under a constitutional death penalty statute, whereas they were originally tried and sentenced before Watson. The Dobbert opinion makes it clear that this is a distinction without ex post facto implications. The Supreme Court in Dobbert held that the new Florida statute was not an ex post facto law both because it was procedural and because it was ameliorative. 432 U.S. [1263]*1263at 294, 97 S.Ct. at 2298. That is, it “neither made criminal a theretofore innocent act, nor aggravated a crime previously committed, nor provided greater punishment, nor changed the proof necessary to convict.” 432 U.S. at 293, 97 S.Ct. at 2298. The “change” in the Arizona statute as a result of the interpretation by Watson is likewise both procedural and ameliorative. Its only effect was to enlarge the ability of defendants to introduce mitigating circumstances at sentencing. Thus, no ex post facto problems arise even with respect to those appellants tried and sentenced before Watson.
Appellants next argue that the invalidation of the previous Arizona sentencing procedure by Watson resulted in the acquisition of a fully matured right in each to receive a life sentence under Section 10, Chapter 138 of the 1973 Arizona Session Laws. This section provides that if the death penalty is held unconstitutional on final appeal, persons previously sentenced to death will receive a life sentence with no possibility of parole for 25 years. It follows, appellants insist, that to subject them to a more severe sentence than life imprisonment is an enlargement of the penalty contrary to the ex post facto prohibition of the Constitution.
We do not agree. Our deference to Arizona’s interpretation of its own laws requires this result. Questions of when and how section 10 takes effect pertain to Arizona law, and have been resolved adversely to appellants by the courts of that state. Section 10 provides for the imposition of a life sentence “[i]n the event the death penalty is held unconstitutional on final appeal.” 1973 Ariz.Sess. Laws § 10, ch. 138. The Watson court held that section 10 was intended to apply only if the death penalty itself was found unconstitutional. 120 Ariz. at 441, 586 P.2d at 1265. An invalidation of sentencing procedures would not make section 10 operative. Therefore, appellants never received a life sentence under Arizona law. We are not empowered to provide such a sentence. Appellants have been, and continue to be, under sentence of death.
VII.
THE DOUBLE JEOPARDY ISSUE
Appellants who were tried and sentenced to death prior to the decision in Watson claim that their resentencing under Watson violates the double jeopardy clause of the Fifth Amendment. We do not agree.
The double jeopardy clause does not prohibit resentencing. Nor does it absolutely prevent an increase in the original sentence on retrial following a reversal of a conviction. North Carolina v. Pearce, 395 U.S. 711, 719-21, 89 S.Ct. 2072, 2077-78, 23 L.Ed.2d 656 (1969). Double jeopardy, of course, does require that upon resentencing credit be given for punishment already endured under the first sentence. 395 U.S. at 718-19, 89 S.Ct. at 2077-78. However, to receive such credit the original punishment must have commenced. Suggs v. Wilson, 403 F.2d 52 (9th Cir. 1968). See the discussion at 513 F.Supp. at 14 n.17.
Inasmuch as none of the appellants can claim to have actually begun serving a death sentence, they once more argue that between sentencing and resentencing, their death penalties were reduced to life imprisonment. The argument proceeds as before: Upon the rendition of the Supreme Court’s decision in Lockett v. Ohio, 438 U.S. 586, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978), or, at the latest, of the Watson decision, they acquired a fully matured right to a life sentence under 1973 Ariz.Sess. Laws § 10, ch. 138. Service of that sentence commenced immediately. Because no credit can be given for this service when a death penalty is imposed, the imposition of the death penalty constitutes a second punishment for a single crime, which is proscribed by the Fifth Amendment guarantee against double jeopardy.
This argument fails as before. Appellants did not acquire a right to a life sentence. We agree with the district court’s view that deference to Arizona’s interpretation of its own laws requires that the life-sentence provision of section 10 be treated as activated only upon invalidation of the death penalty itself. See Watson, 120 Ariz. at 453, 586 P.2d at 1265.
[1264]*1264Appellants also argue that, regardless of section 10, there exists a common-law doctrine that automatically reduces a death sentence to life imprisonment immediately upon invalidation of the state’s death penalty law. We agree with the district court that the California cases cited by appellants do not establish such a doctrine, and that no such doctrine exists.9
Because the Watson court did not find the death penalty as such unconstitutional, appellants occupy a position identical to that of any convicted criminal who has had a sentence vacated for procedural irregularities. They are entitled to resentencing under correct procedures, no more and no less. Nor can resentencing of the appellants here result in a more severe sentence than already has been imposed. To impose the same sentence following vacation of the original sentence for procedural error does not encounter the barrier of double jeopardy.
Next, appellants invoke Bullington v. Missouri, 451 U.S. 430, 101 S.Ct. 1852, 68 L.Ed.2d 270 (1981), in arguing that the Watson resentencing procedures are defective. They insist that their first sentencing constituted an implicit acquittal of each aggravating circumstance found not to exist in that proceeding, and that Bullington prevents a contrary finding on resentencing. We do not agree.10
Bullington is distinguishable. There the petitioner, Bullington, was convicted of murder and sentenced to life imprisonment rather than death under a Missouri death penalty statute providing for a separate penalty phase of the trial before the judge and jury to determine which of the two authorized punishments, death or life imprisonment, should be applied. At the penalty phase under Missouri procedure, the jury hears opening and closing arguments of counsel, evidence of statutory aggravating circumstances, evidence of mitigating circumstances, and instructions from the judge. To impose the death penalty, the jury must find unanimously beyond a reasonable doubt that at least one of the statutory aggravating circumstances exists, must set forth and list the aggravating circumstances it finds, and find that the aggravating circumstances found are sufficient to warrant the imposition of the death penalty. The jury must also determine that the aggravating circumstances are not outweighed by any mitigating circumstances. Its findings are binding upon the trial court judge. The Bullington Court found this procedure so like a trial on guilt that the rendition of a life sentence was a finding that the government had failed to prove its case for the imposition of the death penalty. Therefore, at Bullington’s retrial the [1265]*1265government could not again seek the death penalty.
The Buffington Court indicated no intention to overrule those cases that permit harsher resentencing where the first sentence was rendered under a more flexible scheme involving discretionary balancing of circumstances by the sentencing body. Further, the Buffington Court did not address the issue of the manner in which individual aggravating circumstances should be treated on resentencing when the original sentence imposed the death penalty-
The present case is clearly distinguishable from Buffington. First, appellants in this case, unlike Bullington, were sentenced to death at their original sentencing. There exists no implied “acquittal” in the case. See Bullington, 451 U.S. 430, 101 S.Ct. 1852, 68 L.Ed.2d 270 (Justice Powell, dissenting). The sentence that can be imposed on resentencing here cannot be more severe than that previously assessed. Fundamentally, the Watson procedures are, using Chief Justice Burger’s words from Dobbert v. Florida, supra, 432 U.S. at 304, 97 S.Ct. at 2303 (Burger, C. J., concurring), “if anything, more favorable to the petitioner” than those it replaced. In addition, the Arizona sentencing procedure, both before and after Watson, bears less resemblance to a trial than did that of Missouri. For example, the Arizona sentencing decision is made by the judge rather than the jury, and the procedure for presenting the evidence in Arizona is much less trial-like. These differences lend weight to our holding that in this case no implied acquittals have been shown to exist.
At the resentencing hearing of at least one of the appellants, evidence of aggravating circumstances was introduced that had not been introduced at the first sentencing hearing. State v. Valencia, 124 Ariz. 139, 602 P.2d 807 (1979) (evidence that appellant was convicted of another crime after the first hearing). In light of our finding that the Watson change in interpretation of section 13-454 is procedural and ameliorative, and in light of our finding that Buffington is distinguishable, we hold that this does not constitute double jeopardy. A resentencing hearing at which any evidence of both aggravating and mitigating circumstances is received does not violate appellants’ constitutional rights, even if the evidence developed or was discovered after the original sentencing hearing or was not introduced there for some other reason.
VIII.
SPEEDY SENTENCING
We agree with the district court that appellants’ speedy sentencing arguments are not appropriately considered in a class action, and we express no opinion on the merits of any individual speedy sentencing claims.
AFFIRMED.