In Keeler v. Superior Court (1970) 2 Cal.3d 619, 87 Cal. Rptr. 481, 470 P.2d 617, the Supreme Court explained the rule of lenity in these terms: "It is the policy of this state to construe a penal statute as favorably to the defendant as its language and the circumstances of its application may reasonably permit; just as in the case of a question of fact, the defendant is entitled to the benefit of every reasonable doubt as to the true interpretation of words or the construction of language used in a statute." ( Id. at p. 631.) "The courts cannot go so far as to create an offense by enlarging a statute, by inserting or deleting words, or by giving the terms used false or unusual meanings. Penal statutes will not be made to reach beyond their plain intent: they include only those offenses coming clearly within the import of their language." ( Id. at p. 632.) The rule of lenity has constitutional underpinnings. Under the separation of powers doctrine, the rule serves to protect the legislature's exclusive authority to define crimes from judicial encroachment. (Keeler, supra, 2 Cal.3d at p. 633.) As a matter of fundamental due process, the rule helps to ensure that citizens are given fair warning of conduct punishable as a crime. (Ibid.) People v. Franklin (1999) 20 Cal.4th 249, 975 P.2d 30, is a case applying the rule of lenity in the context of section 290. Franklin had been convicted of sex offenses against children in 1985. ( Franklin, supra, at p. 252.) After initially registering in 1989, Franklin failed to notify authorities of any of his address changes, including his move from California to Texas in 1995. (Ibid.) Charged with various registration violations, new molestation offenses, and felony "strikes," Franklin was returned to California for trial. (Ibid.) In return for Franklin's waiver of a jury trial, the prosecutor dropped the new molestation charges and went to trial on the registration charges. (Ibid.) The trial court found Franklin guilty of violating section 290 based solely on his failure to notify authorities when he moved to Texas. (Ibid.) He was sentenced him to state prison for 25 years to life under the Three Strikes law. (Ibid.)