concurring in part and dissenting in part.
I concur in Parts I — III of the majority’s opinion. I disagree with Part IV because I do not think that this particular offense requires proof of general intent. I write separately to explain why.
I. Statutory Language
I begin, as I must, with the plain language of the governing statute. People v. Dist. Court, 713 P.2d 918, 921 (Colo.1986). Jonathan W. Lopez was charged with failing to register as a sex offender under Colo. Sess. Laws 1998, ch. 139, § 18-3-412.5(4)(a)(I) at 393 (now codified as § 18-3-412.5(1)(a), C.R.S.2005). As set forth in the former § 18 — 3—412.5(4)(a)(I), this offense contains no culpable mental state:
(4)(a) Any person who is required to register pursuant to subsection (1) of this section and who commits any of the acts specified in this paragraph (a) commits the offense of failure to register as a sex offender:
(I) Failure to register pursuant to this section ....
What are we to make of the fact that the statute contains no culpable mental state? Quoting People v. Gross, 830 P.2d 933, 940 (Colo.1992), and People v. Moore, 674 P.2d 354, 358 (Colo.1984), the majority relies on the principle that “legislative silence” cannot be construed as evidence of intent to dispense with proof of a culpable mental state.
Although I accept the principle articulated in Gross and Moore, I do not agree that it applies here. In the context of the offense at issue, the absence of a culpable mental state is significant.
A. Statute on Implied Culpability
The principle articulated in Gross and Moore clearly applies when the proscribed conduct necessarily involves a culpable mental state. In such situations, courts will not construe the absence of an express mental state requirement as evidence of intent to create a strict liability offense. Instead, under § 18-1-503(2), C.R.S.2005, courts will infer a culpable mental state element. See People v. Gross, supra, 830 P.2d at 940 (citing § 18-1-503(2)); People v. Moore, supra, 674 P.2d at 358 (same).
Section 18-1-503(2) does not apply here because the proscribed conduct — failing to register — does not necessarily involve general intent. For example, a sex offender who must register on his birthday may fail to register “unknowingly” if he is unaware that his birthday has arrived. See § 18-1-105(6), C.R.S.2005 (a person acts “knowingly” with respect to a circumstance when he or she is aware that such circumstance exists).
B. Common Law Offense vs. Regulatory Offense
The principle articulated in Gross and Moore also applies if the offense is a traditional crime that has its origins in the common law. See United States v. United States Gypsum Co., 438 U.S. 422, 437, 98 S.Ct. 2864, 2873, 57 L.Ed.2d 854 (1978); People v. Washb*114urn, 197 Colo. 419, 422, 593 P.2d 962, 964 (1979). For these kinds of offenses, courts require “some indication of [legislative] intent, express or implied, to dispense with mens rea as an element.” Staples v. United States, 511 U.S. 600, 606, 114 S.Ct. 1793, 1797, 128 L.Ed.2d 608 (1994).
Here, we are in a different realm. Failure to register as a sex offender is not a traditional crime rooted in the common law; it is a modern regulatory offense created by the legislature. See Jamison v. People, 988 P.2d 177, 180 (Colo.App.1999) (discussing the regulatory purpose of sex offender registration). Thus, instead of discounting the absence of a culpable mental state as mere silence, we may consider whether it “should be interpreted as dispensing with conventional mens rea requirements.” Staples v. United States, supra, 511 U.S. at 607, 114 S.Ct. at 1798.
C. Strict Liability Offenses
The .legislature has instructed us that an offense is one of strict liability if it is premised on nothing more than a voluntary act or omission:
The minimum requirement for criminal liability is the performance by a person of conduct which includes a voluntary act or the omission to perform an act which he is physically capable of performing. If that conduct is all that is required for commission of a particular offense, or if an offense or some material element thereof does not require a culpable mental state on the part of the actor, the offense is one of “strict liability.” If a culpable mental state on the part of the actor is required with respect to any material element of an offense, the offense is one of “mental culpability.”
Section 18-1-502, C.R.S.2005.
Here, the offense plainly requires proof of nothing more than the failure to perform an act that is affirmatively required by law. Thus, under § 18-1-502, we should view the governing statutory language as evidence of an intent to create a strict liability offense.
II. Statutory History
The statutory history provides additional evidence of the intent to create a strict liability offense. It suggests that the legislature purposely omitted a culpable mental state from the provision at issue.
In 1991, when it created the offense of failing to register as a sex offender, the legislature described two ways of violating the statute. Neither of these required proof of a culpable mental state:
Any person who fails to register pursuant to subsections (1) and (2) of this section, or any person who submits a registration form containing false information, commits the offense of failure to register as a sex offender against children. Failure to register as a sex offender against children is a class 2 misdemeanor. Any second or subsequent offense is a class 6 felony.
Colo. Sess. Laws 1991, ch. 69, § 18-3-412.5(3) at 394 (now codified with amendments as § 18-3-412.5(1)(a) & (b), C.R.S. 2005).
Since its enactment, § 18-3-412.5 has been amended ten times. Yet the legislature has never added the word “knowingly” to the text at issue. This is significant, particularly because the legislature included a culpable mental state in some amendments:
• In 1999, the legislature broadened the offense to include the act of “[k]nowingly providing false information to department of corrections personnel or department of human services personnel concerning the address where the person plans to reside upon release.” Colo. Sess. Laws 1999, ch. 286, § 18-3-412.5(4)(a)(III.5) at 1151 (now codified with amendments as § 18-3-412.5(1)(e), C.R.S.2005).
• In 2002, the legislature again broadened the offense to include “knowingly providing false information to a probation department employee, to a community corrections administrator or his or her designee, or to a judge or magistrate when receiving notice ... of the duty to register.” See Colo. Sess. Laws 2002, ch. 297, § 18-3-412.5(1)(c) at 1179.
It therefore appears that the legislature chose to require proof of culpability for certain acts and to dispense with this requirement for other types of violations, including the one at issue. See People v. Wilson, 972 *115P.2d 701, 703-04 (Colo.App.1998) (-when the legislature added subsections that required a culpable mental state, it did not add a mental state to the existing subsection; this suggests that the legislature intended the existing subsection to describe a strict liability offense).
III. Constitutional Avoidance
If the absence of a culpable mental state creates serious concerns about the statute’s constitutionality, courts may select a plausible interpretation that avoids the constitutional question. Clark v. Martinez, 543 U.S. 371, 380-81, 125 S.Ct. 716, 724, 160 L.Ed.2d 734 (2005); People v. Zapotocky, 869 P.2d 1234, 1240 (Colo.1994).
Here, it is unnecessary to “read in” a culpable mental state under the canon of constitutional avoidance. There is no serious doubt about the constitutionality of this statute, even if it is interpreted as a strict liability offense.
A. Due Process Limits
Although the United States Supreme Court has never defined a due process limit on offenses that lack culpable mental states, see Morissette v. United States, 342 U.S. 246, 260, 72 S.Ct. 240, 248, 96 L.Ed. 288 (1952), there is no serious doubt that a state legislature may create an offense that carries the exposure of a class 5 felony without requiring proof of a culpable mental state. See People v. Rostad, 669 P.2d 126 (Colo.1983) (liability for vehicular homicide — currently a class 3 felony under § 18-3-106(1)(b)(I), C.R.S. 2005 — premised solely on the defendant’s voluntary conduct of operating a motor vehicle while intoxicated). This is especially true when, as here, the penalty is for a second offense. See Colo. Sess. Laws 2001, ch. 176, § 18-3-412.5(4)(b)(I) at 567 (now codified with amendments as § 18-3-412.5(2)(a), C.R.S.2005).
B. Notice of Duty to Register
The Colorado Sex Offender Registration Act requires that sex offenders receive notice of the duty to register. See §§ 16-22-105 to 16-22-107, C.R.S.2005. The notice provisions ensure that failure-to-register offenses may be prosecuted without violating the due process rule announced in Lambert v. California, 355 U.S. 225, 78 S.Ct. 240, 2 L.Ed.2d 228 (1957). Thus, the provisions alleviate doubt about the facial constitutionality of a statute that creates a strict liability offense of failure to register as a sex offender. See State v. Bryant, 359 N.C. 554, 614 S.E.2d 479, 486 (2005).
If a particular sex offender does not receive notice of the duty to register, he may bring an individual challenge under Lambert, showing (1) his conduct was wholly passive, and (2) there were no circumstances that should have alerted him to the consequences of failing to register. See State v. Bryant, supra, 614 S.E.2d at 488; see also United States v. Denis, 297 F.3d 25, 29 (1st Cir.2002).
IV. Policy Considerations
The offense of failure to register as a sex offender has an obvious purpose: to encourage strict compliance with Colorado’s sex offender registration laws. The majority’s interpretation may undermine this purpose by allowing sex offenders to interpose new defenses to enforcement.
One such defense will take the form of the assertion: “I forgot.” Under the majority’s interpretation, this assertion (if believed) would defeat proof that a sex offender “knowingly” failed to register.
California courts have negated the “I forgot” defense, not because it is logically irrelevant, but because it would eviscerate that state’s regulatory scheme and thus could not have been intended by the legislature. See People v. Barker, 34 Cal.4th 345, 18 Cal.Rptr.3d 260, 96 P.3d 507 (2004) (“I forgot” is not a defense even though the statute requires proof of a “willful” failure to register).
Colorado courts need not address the “I forgot” defense. - Instead, we should recognize that the legislature intended to create a strict liability offense when it omitted a culpable mental state from the provision at issue.
*116For these reasons, I respectfully dissent from Part IV of the majority’s opinion.