Defendant was indicted for committing three felonies between June 1 and September 1,1986: (1) using a child in a display of sexually explicit conduct, ORS 163.670; (2) dealing in depictions of a child’s sexual conduct, former ORS 163.673 (1987), repealed by Or Laws 1995, ch 768, § 16; and (3) sexual abuse in the first degree, ORS 163.425 (1985). According to the indictment, all victims were under 18 years of age at the time of the crimes. A warrant for defendant’s arrest issued on October 10,1991.
Defendant demurred, arguing that the state was time-barred from prosecuting him.1 Specifically, defendant argued that his prosecution was barred by the three-year statute of limitations that was in effect when he allegedly committed the crimes, ORS 131.125 (1985). After that three-year period had expired, the legislature amended ORS 131.125 to extend the limitations period to six years with respect to the particular crimes at issue. Defendant argued that, assuming that the legislature intended for the amendments to apply to revive a previously time-barred prosecution, that application of the law would violate the state and federal constitutional prohibitions against ex post facto laws.2 The trial court allowed the demurrer and entered an order dismissing the indictment.
On the state’s appeal,3 a divided Court of Appeals, sitting in banc, affirmed. State v. Cookman, 127 Or App 283, *24873 P2d 335 (1994). The lead opinion stated that “revival of a lapsed prosecution is so extremely unfair that it transgresses the recognized due process principle of ‘fundamental fairness.’ ” 127 Or App at 286.
A concurrence agreed with the outcome, but would not reach the due process issue, because “the trial court’s judgment can and should be affirmed on state constitutional grounds.” Id. at 290 (Leeson, J., concurring). The concurrence then stated that ORS 131.125(2), as amended in 1991 and as applied to defendant, “deprives him of a vested and complete procedural defense” in violation of the Oregon Constitution’s prohibition against ex post facto laws. Id. at 293.
A four-judge dissent stated that defendant had not raised a due process issue at trial, id. at 293 (De Muniz, J., dissenting); that, in any case, the majority’s due process analysis was in error, id. at 295-96; and that the dissent would have held that the ex post facto provisions of the state and federal constitutions do not bar the prosecution, id. at 299.
The state petitioned for review, and we allowed the petition. For the reasons that follow, we affirm the decision of the Court of Appeals and the order of the circuit court.
STATUTORY ANALYSIS
ORS 131.105 provides that a “criminal action must be commenced within the period of limitation prescribed in ORS 131.125 to 131.155.” Before 1989, ORS 131.125(2)(a) provided that a prosecution must be commenced within three years after the commission of a felony other than murder or manslaughter. That provision was in effect when defendant allegedly committed the crimes at issue. Under it, the state had to commence its prosecution of defendant by, at the latest, September 1, 1989. It did not. A prosecution is “commenced” when a “warrant or other process is issued.” ORS 131.135. That occurred, in this case, on October 10, 1991. This prosecution thus is untimely under the pre-1989 version of ORS 131.125.
In 1989, the legislature amended ORS 135.125 to lengthen the period of limitations for certain felonies, including the ones for which defendant was indicted, to six years *25from the time the crime was committed, if the victim was less than 18 at the time of the crime. Or Laws 1989, ch 831, § 1. Those amendments took effect on October 3,1989. However, by that date, the period of limitations in which the state had to prosecute defendant under the pre-1989 statute already had expired.4
In 1991, the legislature again amended ORS 131.125. Among those amendments was section 1 of an Act contained in Oregon Laws 1991, chapter 388:
“ORS 131.125 is amended to read:
* * * *
“(2) A prosecution for any of the following felonies may be commenced within six years after the commission of the crime or, if the victim [,] at the time of the crime [,] was under 18 years of age, anytime before the victim attains 24 years of age or within six years after the offense is reported to a law enforcement agency or other governmental agency, whichever occurs first:
:f: sf: ifc if:
“(j) Sexual abuse in the first degree under ORS 163.425.
“(k) Using a child in a display of sexual conduct under ORS 163.670.
“(L) Dealing in depictions of a child’s sexual conduct under ORS 163.673.” (Deletions in brackets; additions in boldface.)
Section 2 of the same Act provided:
“The amendments to ORS 131.125 by section 1 of this Act apply to all causes of action whether arising before, on or after the effective date of this Act, and shall act to revive any cause of action barred by ORS 131.125 (1989 Edition) if the action is commenced within the time allowed by ORS 131.125 as amended by section 1 of this Act.”5
*26The effective date of the Act was September 29,1991. It is the provisions of section 2 on which the state relies to argue that the lengthened criminal statute of limitations applies retroactively to revive prosecutions previously barred before 1989.
The Court of Appeals held that the legislature intended the 1991 amendments to revive the present prosecution, even though that prosecution was barred by the pre-1989 version of ORS 131.125, rather than by “ORS 131.125 (1989 Edition).” 127 Or App at 285. The interpretive question here is whether the legislature intended to revive only prosecutions barred by the 1989 version of ORS 131.125 or also to revive prosecutions barred by the pre-1989 version of ORS 131.125.
In interpreting a statute, we seek to discern the legislature’s intent. PGE v. Bureau of Labor and Industries, 317 Or 606, 610, 859 P2d 1143 (1993). At the first level of analysis, we consider text and context. Ibid.
Section 2 of the 1991 Act, quoted above, begins by providing that the amendments to the statutes of limitation “apply to all causes of action whether arising before, on or after the effective date of this Act.” (Emphasis added.) With respect to crimes, a “cause of action” arises when the crime is committed. The broad sweep of the first half of section 2 covers the crimes alleged here. The second half of section 2 creates an ambiguity, however, by specifying that the amendments are meant to “revive any cause of action barred by ORS 131.125 (1989 Edition).” (Emphasis added.) The context does not resolve that ambiguity in the text.
Because it is not clear from text and context whether the legislature intended the 1991 amendments to revive a prosecution otherwise barred by the pre-1989 version of ORS 131.125, we turn to legislative history. See PGE, 317 Or at 611-12 (setting forth method). We have examined the legislative history, but it provides no direct answer or insight to resolve this question. Therefore, we move to the third level of analysis by resorting to general maxims of statutory construction. See ibid, (setting forth method).
The most apt maxim here is that the court will attempt to determine how the legislature would have *27intended the statute to apply had it considered the issue. See Steelman-Duff, Inc. v. Dept. of Transportation, 323 Or 220, 235, 915 P2d 958 (1996) (describing and applying principle). With that maxim in mind, we believe that the 1991 legislature would have intended the statute to revive prosecutions that otherwise would be barred by the pre-1989 version of ORS 131.125, as well as prosecutions that otherwise would be barred by the 1989 version.
First, it is quite clear that the substantive 1991 amendments were intended to make it easier for the state to prosecute the listed crimes. Second, the basic thrust of Oregon Laws 1991, chapter 388, section 2, is to take advantage of retroactivity as broadly as possible. Third, the legislature had before it the opinion of at least one member to the effect that retroactive revival of a time-barred prosecution did not violate constitutional proscriptions against ex post facto laws. Tape recording, House Judiciary Family Justice Subcommittee, February 13, 1991, Tape 31, Side A at 60-67 (comments of Representative Edmunson). In the circumstances, we see no reason why the legislature would have intended that the advantage conferred on the state be limited to revival of prosecutions barred only by the 1989 version of the statute of limitations. We hold, therefore, that the 1991 amendments are to be read to revive all prosecutions of the listed crimes when those prosecutions would have been time-barred under the 1989 or the pre-1989 version of ORS 131.125, provided that the prosecution is commenced within the time allowed by the 1991 amendments.
STATE CONSTITUTIONAL ANALYSIS
This court considers state constitutional claims before considering federal constitutional claims. State v. Kennedy, 295 Or 260, 262, 666 P2d 1316 (1983); Sterling v. Cupp, 290 Or 611, 614, 625 P2d 123 (1981). Accordingly, we turn to the issue raised under Article I, section 21, of the Oregon Constitution, which prohibits ex post facto laws. In interpreting a provision of the Oregon Constitution, we consider “[i]ts specific wording, the case law surrounding it, and the historical circumstances that led to its creation.” Priest v. Pearce, 314 Or 411, 415-16, 840 P2d 65 (1992).
*281. Wording
Article I, section 21, provides, simply, that “[n]o ex-post facto law * * * shall ever be passed.” That is, it forbids the passage of laws “after the fact.”
This provision ought not be read to forbid laws from having any retrospective application, however. Laws are, by design, applicable to historical facts. See Bryant Smith, Retroactive Laws and Vested Rights, 5 Tex L Rev 231, 233 (1927) (discussing concept of retroactivity). Rather, from its wording, the provision forbids only those laws that are designed to.be applicable to facts that have occurred before the passage of the laws. In short, the focus of this provision is on the time when a law takes effect, State v. Robertson, 293 Or 402, 408 n 4, 649 P2d 569 (1982): A law may not affect events to which it relates retroactively, if those events occurred before the law’s effective date.
2. Cases
Despite Article I, section 21’s seemingly broad scope, this court has restricted that provision’s prohibition to criminal laws, Fisher et al. v. City of Astoria, 126 Or 268, 286, 269 P 853 (1928), and, further, to only certain kinds of criminal laws:
“Generally speaking, ex post facto laws punish acts that were legal at the time they occurred, change the punishment for those acts,[6] or deprive the defendant of a defense for those acts.” State v. Gallant, 307 Or 152, 155, 764 P2d 920 (1988).
In a similar vein, this court has quoted with approval the United States Supreme Court’s understanding of the scope of the ex post facto provision contained in Article I, section 10, of the federal constitution, on the assumption that that provision’s scope is similar to the scope of Article I, section 21:
“The Court explained the meaning of the Ex Post Facto Clause as follows:
*29“ ‘ “It is settled, by decisions of this Court so well known that their citation may be dispensed with, that 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, is prohibited as ex post facto.” ’ [Collins v. Youngblood, 497 US 37, 42, 110 S Ct 2715, 111 L Ed 2d 30 (1990)] (quoting Beazell v. Ohio, 269 US 167, 169-70, 46 S Ct 68, 70 L Ed 216 (1925)).
“In summary, the Court stated, ‘[[legislatures may not retroactively alter the definitions of crimes or increase the punishment for criminal acts.’ Id. at 42.” State v. Wille, 317 Or 487, 502, 858 P2d 128 (1993).7
The state has conceded before this court that count 2 of the indictment — charging defendant with dealing in depictions of a child’s sexual conduct, ORS 163.673 — falls within one of the above-described categories of penal law. Specifically, the state concedes that application of ORS 163.673 to defendant violates Article I, section 21, because that application would punish an act that was legal when done.
From our independent analysis, the state’s concession appears to be well taken.8 Defendant allegedly violated ORS 163.673 between June 1 and September 1, 1986. ORS 163.673 was first enacted by the 1987 legislature. Or Laws 1987, ch 864, § 4. Neither the state nor this court has found anything to suggest that the conduct made criminal by that law previously had been made criminal under some other statute. Thus, ORS 163.673, as applied to defendant, punishes him retroactively for conduct that was not criminal at all when done. That application violates Article I, section 21. Defendant cannot be convicted for engaging in conduct that was not, at the time of the conduct, a crime.
*30As for the remaining two felony counts — using a child in a display of sexually explicit conduct and sexual abuse in the first degree — the question still remains whether Article I, section 21, permits the retroactive application of an amended, and longer, statute of limitations to revive prosecutions that already were time-barred before the. amendment took effect.
3. History
Article I, section 21, was adopted by convention in 1857. The record of that convention does not indicate the convention’s intent in adopting the provision. See Charles Henry Carey, The Oregon Constitution and Proceedings and Debates of the Constitutional Convention of 1857 (1926). However, it appears that Article I, section 21, was derived from the Indiana Constitution of 1851, specifically, Article I, section 24, of that Constitution.9 W. C. Palmer, The Sources of the Oregon Constitution, 5 Or L Rev 200, 202 (1926). Article I, section 24, of the 1851 Indiana Constitution is itself substantially similar to Article I, section 18, of the 1816 Indiana Constitution.10
In 1822, the Indiana Supreme Court construed the 1816 provision as follows:11
“The words ex post facto have a definite, technical signification. The plain and obvious meaning of this prohibition is, that the Legislature shall not pass any law, after a fact done by any citizen, which shall have relation to that fact, so as to punish that which was innocent when done; or to add to the punishment of that which was criminal; or to increase the malignity of a crime; or to retrench the rules of evidence, so as to make conviction more easy.” Strong v. The State, 1 Blackf 193, 196 (1822) (citing Calder v. Bull, 3 US (3 Dall) 386, 1 L Ed 648 (1798), among other authorities).12
*31In 1845, that court made explicit what was implicit in Strong; that the ex post facto clause of the 1816 Indiana Constitution was limited to criminal laws only. Andrews v. Russell, 7 Blackf 474, 475 (1845).
It is readily obvious that those Indiana decisions do not add much to this court’s previously announced understanding of Article I, section 21, discussed above. But see Gallant, 307 Or at 155 (application of a uniform rule of evidence of general application that “did not affect a substantive right” in a trial for a crime committed before the rule was adopted does not violate Article I, section 21).
Be that as it may, the history of the ex post facto clauses found in the various state constitutions,13 as well as in the federal constitution, extends beyond the founding of our republic, and may be traced back to English law, and further back to Roman law, Hall v. Northwest Outward Bound School, 280 Or 655, 658, 572 P2d 1007 (1977), if not to Greek law, Elmer E. Smead, The Rule Against Retroactive Legislation: A Basic Principle of Jurisprudence, 20 Minn L Rev 775, 775 (1936). Thus, for instance, Blackstone, writing in the 1760s, instructs us:
“[Wlhatever way is made use of [to notify the people of the legislature’s resolutions], it is incumbent on the promulgators to do it in the most public and perspicuous manner; not like Caligula, who (according to Dio Cassius) wrote his laws in a very small character, and hung them up on high pillars, the more effectually to insnare the people. There is still a more unreasonable method than this, which is called the making of laws ex post facto-, when after an action (indifferent in itself) is committed, the legislator then for the first time declares it to have been a crime, and inflicts a punishment upon the person who has committed it. Here it is impossible that the party could foresee that an action, innocent when it was done, should be afterwards converted to guilt by a subsequent law; he had therefore no cause to abstain from it; and all punishment for not abstaining must of consequence be cruel and unjust. All laws should be therefore made to commence in futuro, and be notified *32before their commencement [.] 1 William Blackstone, Commentaries on the Laws of England 46 (1807) (footnote omitted).
Closer to home, James Madison, in urging the State of New York to ratify the federal constitution, between 1787 and 1788, wrote:
“Bills of attainder, ex post facto laws, and laws impairing the obligation of contracts, are contrary to the first principles of the social compact, and to every principle of sound legislation. The two former are expressly prohibited by the declarations prefixed to some of the state constitutions, and all of them are prohibited by the spirit and scope of these fundamental charters. Our own experience has taught us, nevertheless, that additional fences against these dangers ought not to be omitted. Very properly, therefore, have the convention added this constitutional bulwark in favor of personal security and private rights; and I am much deceived, if they have not, in so doing, as faithfully consulted the genuine sentiments, as the undoubted interests of their constituents. The sober people of America are weary of the fluctuating policy which has directed the public councils.” The Federalist No. 44 (James Madison).
It was to Blackstone, as well as to the “author of the Federalist,” to whom United States Supreme Court Justice Chase turned, in 1798, to support his now classic formulation of the ex post facto prohibition:
“I will state what laws I consider ex post facto laws, within the words and the intent of the prohibition. 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 rules of evidence, and receives less, or different testimony, than the law required at the time of the commission of the offence, in order to convict the offender. All these, and similar laws, are manifestly unjust and oppressive. * * * The celebrated and judicious Sir William Blackstone, in his commentaries, considers an ex post facto law precisely in the same light as I have done. His opinion is confirmed by his successor, Mr. Wooddeson; and by the author of the Federalist, who I *33esteem superior to both, for his extensive and accurate knowledge of the true principles of government.” Calder, 3 US (3 Dall) at 390-91 (seriatim opinion).
Whatever the merits of Justice Chase’s formulation with regard to the federal constitution,14 as with Blackstone’s Commentaries and The Federalist, Chase’s opinion was available to the framers of the Oregon Constitution. Perhaps more importantly, it also was cited by the Indiana Supreme Court in Strong, a decision that was available to the framers of the Oregon Constitution when they decided to adopt the Indiana ex post facto provision in our state constitution.
4. Application of Principles
With the foregoing materials in mind, we return to the issue at hand — whether application of the 1991 amendments to revive defendant’s time-barred prosecution violates Article I, section 21 — and to this court’s previously announced categories of penal law that are proscribed by Article I, section 21. To recapitulate, the categories are: (1) laws that punish acts that were legal before the enactment of those laws; (2) laws that impose greater or additional punishment than that available before the enactments of those laws; and (3) laws that deprive the defendant of a defense. Wille, 317 Or at 502; Gallant, 307 Or at 155.
As already noted, application of the 1991 amendments to revive defendant’s prosecution for two kinds of conduct committed in 1986 does not punish acts that were innocent before the amendments. Thus, the question becomes whether application of those amendments to defendant imposes a more burdensome punishment or deprives him of a defense.
*34The expiration of a criminal statute of limitations confers a complete defense to a prosecution for a crime. An application of an extended period of limitations to revive a prosecution that already became time-barred before the effective date of the extension necessarily deprives a defendant of that complete defense.
An expired period of limitations operates like a legislative waiver, pardon, or grant of immunity, on a condition (the passage of a specified period of time) that has been fully met. Whatever the most apt analogy, the statute of limitations gives a defendant, on the date the specified period expires, a complete defense. The sovereign, having surrendered utterly its right to prosecute after a certain time, cannot, after that time, revive its right to prosecute without running afoul of the ex post facto prohibition.
We hold that Article I, section 21, of the Oregon Constitution prohibits the retroactive application of an amended criminal statute of limitations, extending the period of limitations, to revive prosecutions that already were time-barred when the amendment took effect. To the extent that Oregon Laws 1991, chapter 388, section 2, requires such a retroactive application, that provision is unconstitutional under Article I, section 21. Accordingly, the trial court did not err in allowing defendant’s demurrer to the indictment. The Court of Appeals did not err in sustaining that order.15
The decision of the Court of Appeals and the order of the circuit court are affirmed.
ORS 135.630 provides, in pertinent part:
“The defendant may demur to the accusatory instrument when it appears upon the face thereof:
«íjc ;j; ‡ ‡
“(5) That the accusatory instrument contains matter which, if true, would constitute a * * * legal bar to the action].]”
Article I, section 21, of the Oregon Constitution, provides:
“No ex-post facto law * * * shall ever be passed].]”
Article I, section 10, clause 1, of the United States Constitution, provides:
“No State shall * * * pass any * * * ex post facto Law.”
At the hearing on defendant’s demurrer, the state also raised an issue as to whether revival of a lapsed prosecution violates due process.
ORS 138.060(1) permits the state to appeal from an order “made prior to trial dismissing or setting aside the accusatory instrument.”
The Court of Appeals decided in State v. Tyler, 108 Or App 378, 815 P2d 1289 (1991), that the legislature did not intend the 1989 amended statute to apply retroactively to prosecutions already barred by the pre-1989 statute at the time the 1989 amendments took effect. The state does not contend that Tyler was wrongly decided.
Section 2 was not codified, but merely noted after ORS 131.125 in the 1991 edition of the Oregon Revised Statutes.
To be more precise, as to the punishment factor, Article I, section 21, prohibits changes in punishment that make the punishment more burdensome. That is, a law must impose additional or increased punishment before it falls within the scope of that prohibition. State v. Wille, 317 Or 487, 502, 858 P2d 128 (1993); State v. Smith, 56 Or 21, 26, 107 P 980 (1910).
This court has previously explained that it cites federal cases when interpreting Oregon law only when it finds the views expressed there persuasive, not because it is bound to do so. Kennedy, 295 Or at 267. This court also has explained that its past reliance on the Supreme Court’s pronouncements when construing Oregon’s law do not imply that the meaning of Oregon’s law is forever fixed to the federal courts’ understanding of analogous federal law. Id. at 271.
See State v. Bea, 318 Or 220, 224, 864 P2d 854 (1993) (court need not accept a concession concerning a legal conclusion).
Article I, section 24, of the Indiana Constitution of 1851, provides: “No expost facto law * * * shall ever be passed.”
Article I, section 18, of the Indiana Constitution of 1816, provided: “No ex post facto law * * * shall ever be made.”
We have been unable to locate any pre-1857 Indiana decisions interpreting the ex post facto provision of the 1851 constitution. See Priest, 314 Or at 418-19 (“decisions made after Oregon’s statehood do not establish the meaning of the earlier-adopted language in the Oregon Constitution”).
Strong held that a retroactive change in the punishment for perjury, from whipping not exceeding 100 stripes to imprisonment not exceeding seven years, was permissible under the ex post facto clause at issue. 1 Blackf at 195-97.
It appears that, at the present time, only six states — Connecticut, Delaware, Hawaii, Kansas, New York, and Vermont — do not prohibit “retroactive,” “retrospective,” or “ex post facto” laws in their constitutions.
It is difficult to tell from whence Chase derived his formulation. It should be evident that neither Blackstone nor Federalist No. 44 specified the workings of the prohibition against ex post facto laws in as great a detail, and in quite the same way, as Chase. It should perhaps be telling that Chase thought, as an initial matter, that “natural law,” defined by “the purposes for which men enter into society,” prohibits the making of ex post facto penal laws or, indeed, of any law that violates “the right to an antecedent lawful private contract,” or “of private property.” Calder, 3 US (3 Dall) at 387-89. As such, Chase believed that the framers ofthe federal constitution introduced the ex post facto clause of that constitution, applicable to the states, out of mere “greater caution.” Id. at 389.
Because of our disposition of the case, we need not reach any federal constitutional issues.