GLICKMAN, Associate Judge:
In 2009, the Council of the District of Columbia enacted a statute, D.C.Code § 22-2511 (2012 Repl.), making it a felony offense for a person to be present in a motor vehicle if the person knows that the vehicle contains a firearm (“PMVCF”), even if the person has no connection to or control over the weapon and is not involved in any wrongdoing whatsoever. This is the first appeal of a PMVCF conviction to come before this court. Appellant Antwaun Conley, joined by the Public Defender Service as amicus curiae, contends that the law is unconstitutional and that the trial court plainly erred in allowing the jury to convict him of this crime.
We agree that the PMVCF statute violates due process. We reach that conclusion for two reasons. First, the essence of the offense is the defendant’s voluntary presence in a vehicle after he learns that it contains a firearm. Yet instead of requiring the government to prove that the defendant’s continued presence was voluntary, § 22-2511 requires the defendant to shoulder the burden of proving, as an affirmative defense, that his presence in the vehicle was involuntary. This shifting of the burden of persuasion with respect to a [273]*273critical component of the crime is incompatible with due process.
Were that the only defect in the statute, it would not necessarily be fatal, for we might sever the constitutionally invalid affirmative defense and construe the remainder of § 22-2511 as imposing on the government the burden to prove that the defendant stayed in the vehicle voluntarily after he learned that it contained a firearm. But burden-shifting is not the statute’s only constitutional defect; it offends due process in another way. As the Supreme Court explained in Lambert v. California,
I. Factual Background
This case began on July 24, 2010, with an early-morning traffic stop by officers of the Metropolitan Police Department of a Honda Accord on Stanton Road in Southeast, Washington, D.C. Appellant was in the driver’s seat and a second man, Kendra Allen, was in the front passenger seat. The police took the two occupants to the rear of the vehicle and held them there while officers shone their flashlights into the passenger compartment. When they did so, they observed a handgun in plain view in the center console between the two front seats. The weapon was loaded. A crime scene search officer later dusted the gun and bullets for fingerprints, but no prints were recovered.
In due course, appellant was charged by indictment with four possessory offenses— unlawful possession of a firearm,3 carrying a pistol without a license,4 possession of an unregistered firearm,5 and unlawful. possession of ammunition6 — plus the non-pos-sessory offense of PMVCF, in violation of D.C.Code § 22-2511. He pleaded not guilty. At trial, his defense was that he neither possessed the gun nor knew it was in the car, and that the weapon must have been placed in the console after he exited the vehicle by either Mr. Allen or one of the police officers.7 Appellant did not challenge the constitutionality of his prosecution for PMVCF.
The judge defined PMVCF for the jury as follows:
[274]*274The- elements of unlawful presence in a motor vehicle containing a firearm, each of which the Government must prove beyond a reasonable doubt, are that one, Mr. Conley was voluntarily in a motor vehicle; two, a firearm was in the motor vehicle; three, Mr. Conley knew the firearm was in [the] motor vehicle; and four, the firearm was not lawfully carried or lawfully transported.[8]
The jury acquitted appellant of all the possessory offenses. It found him guilty only of PMVCF. For that offense, the judge sentenced appellant to thirty-four months in prison.
II. The Statutory Offense
D.C.Code § 22-2511, the PMVCF statute, reads in pertinent part as follows:
(a) It is unlawful for a person to be voluntarily in a motor vehicle if that person knows that a firearm is in the vehicle, unless the firearm is being lawfully carried or lawfully transported.
(b) It shall be an affirmative defense to this offense, which the defendant must prove by a preponderance of the evidence, that the defendant, upon learning that a firearm was in the vehicle, had the specific intent to immediately leave the vehicle, but did not have a reasonable opportunity under the circumstances to do so.
The offense is a felony, punishable by up to five years in prison.9
The statute was enacted as part of the Omnibus Public Safety and Justice Amendment Act of 2009.10 As the Council’s Committee on Public Safety and the Judiciary explained in its report on the legislation, the new offense of PMVCF was created in order to allow convictions to be obtained when a firearm is found in a car with more than one occupant and the government cannot prove who possessed it:
The issue that this provision seeks to address is when a car is stopped with multiple occupants and a firearm is present in the vehicle — the police are unable to prove who was in possession of the firearm. Even if the police believe they know who possessed the firearm— constructive possession with multiple occupants in the car is very difficult to prove at trial. The proposal therefore seeks to make it illegal for every occupant to be present in the vehicle as opposed to just the occupant that possessed the weapon.[11]
[275]*275As originally proposed, subsection (a) of the PMVCF statute would have made it “unlawful for a person to be in a motor vehicle if that person knows that a firearm is in the vehicle”12 without regard to whether the person is in the vehicle voluntarily, and the statute did not include- an affirmative defense of involuntariness such as that which now appears in subsection (b). The Public Defender Service for the District, of Columbia and the D.C. Association of Criminal Defense Lawyers opposed the legislation, among other reasons because it would make felons of citizens who wanted nothing to do with the firearm and were innocent of any wrongdoing.13 In response to the criticisms, the Committee on Public Safety and the Judiciary revised the statute to its current form. The alterations, which included adding the word “voluntarily” to subsection (a) and creating the affirmative defense now set forth in subsection (b), were intended “to ensure,” inter alia, that the PMVCF statute would “not be used against those who ... had no ability to safely distance themselves from the firearm.”14 “In addition,” the Committee stated, its “recommended language makes it clear that there must be some deliberate decision on the part of the accused to be in a vehicle with an illegal firearm present.”15
III. The Availability and Scope of Review
In -the trial court, appellant did not raise a constitutional challenge to his prosecution for PMVCF. As a threshold matter, therefore, we must consider whether his attack on the constitutionality of D.C.Code § 22-2511 is properly before us and the scope of our review if it is. The government argues that appellant waived his claim of unconstitutionality by failing to raise it as a defect in the indictment prior to trial pursuant to Criminal Rule 12(b)(2).16 However, we do not believe that provision is triggered here.17
[276]*276Although Rule 12(b)(2) provides generally that objections based on defects in the indictment are waived unless raised prior to trial, it makes an exception for objections that the indictment “fails to show jurisdiction in the Court or to charge an offense.”18 Those objections, the Rule states, “shall be noticed by the Court at any time during the pendency of the proceedings.” Federal courts, construing a substantially identical provision in the Federal Rules of Criminal Procedure, have held that “[t]he defense of failure of an indictment to' charge an offense includes the claim that the statute apparently creating the offense is unconstitutional” and that such a claim therefore is not waived by failing to raise it before trial.19 We agree with that conclusion. An indictment clearly fails to charge an offense -if the Constitution precludes the prosecution.
Accordingly, appellant did not waive his constitutional challenge to the PMVCF statute. His failure to present his claim to the trial court, however, comes at a price — namely, that on appeal his claim “is subject to the rigors of plain error review.”20 This means appellant must do more than simply demonstrate (1) that an error was committed in his trial court proceedings; he also must show (2) that the error is plain under current law and (3) that it affected his substantial rights. We then may exercise our discretion to notice the forfeited error and grant appellant relief, but only if “(4) the error seriously affects the fairness, integrity, or public reputation of judicial proceedings.” 21
IV. Legal Discussion
A. The Constitutionality of § 22-2511
The first prong of plain error analysis — whether the trial court erred in allowing appellant to be convicted for PMVCF — requires us to evaluate the merits of appellant’s claim that D.C.Code § 22-2511 is violative of due process on its face.22 A facial challenge imposes a [277]*277“heavy burden” on the claimant to establish that “the law is unconstitutional in all of its applications.”23 We look only to whether the statute properly proscribes criminal conduct; we do not examine whether appellant’s conduct could have been criminalized under a hypothetical statute.24 Thus, in a facial challenge, “the claimed constitutional violation inheres in the terms of the statute, not its application.” 25 In deciding whether the challenge is meritorious, appellant’s “personal situation becomes irrelevant.” It is enough that ‘“[w]e have only the [statute] itself and the ‘statement of basis and purpose that accompanied its promulgation.’ ”26 Appellant must demonstrate that the terms of the statute, “measured against the relevant constitutional doctrine, and independent of the constitutionality of particular applications, contain! ] a constitutional infirmity that invalidates the statute in its entirety.”27 Accordingly, if § 22-2511 fails to require the government to prove everything the Constitution requires it to prove for a criminal sanction to be imposed, as appellant contends, and if the legislative design and the limits of the judicial function do not permit us to read the critical missing elements into the statute, then appellant has carried his burden of showing that every application of § 22-2511 is unconstitutional — even if a validly written statute could have reached appellant’s particular conduct.
We begin by considering the argument that § 22-2511 unconstitutionally shifts the burden of persuasion to the defense with respect to an essential element of the offense, i.e., the defendant’s voluntary presence in the vehicle. Assuming that it is possible to overcome this argument by a suitable construction of the statute, we go on to consider whether § 22-2511 nonetheless fails to pass constitutional muster under the principles explained by the Supreme Court in Lambert.28
1. Shifting the Burden of Persuasion
Subsection (a) of § 22-2511 makes it unlawful for a person to “voluntarily be” in a motor vehicle if the person knows there is a firearm in the vehicle, unless the firearm is being carried or transported [278]*278lawfully. In response to appellant’s criticism that the offense defined in the statute lacks the essential component of a prohibited actus reus (culpable conduct of some kind),29 the government explains that subsection (a) creates a valid crime .of omission — the essence of which is a failure to perform an act that one has a legal duty to perform under the circumstances.30 Specifically, the government argues, criminalizing voluntary presence in a car by one who knows it contains a firearm is equivalent to criminalizing the voluntary failure to leave the car when one knows there is a firearm in it. In other words, according to the government, “[t]he statute criminalizes failing to leave a car as soon as reasonably possible once one learns that a firearm is present where the firearm is not being lawfully carried or transported.”31
But if the offense created in § 22-2511(a) is the voluntary failure to leave a motor vehicle as soon as reasonably possible after learning that it contains a firearm, subsection (b) creates a problem. Subsection (b) requires the defendant to prove by a preponderance of the evidence the affirmative defense that he remained in the vehicle against his will because he had no reasonable opportunity to leave it. This seems to mean that instead of the government having to prove that the defendant remained in the vehicle voluntarily, the defendant has to disprove it, i.e., to prove that he remained involuntarily. This apparent shift in the burden of proof with respect to the element of voluntary presence implicates fundamental principles of due process.
The Due Process Clause “protects the accused against conviction except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged.”32 This means it is up to the prosecution “to prove beyond a reasonable doubt all of the elements included in the definition of the offense....”33 The defendant therefore may not be required to “prove the critical fact in dispute,”34 and “the burden of persuasion may not be shifted to the defendant with respect to a defense that serves only to negate an element of the offense that the government is required to prove.”35 Thus, because voluntary pres[279]*279ence is an undisputed element of the offense of PMVCF, the Due Process Clause forbids shifting the burden to the defendant to negate that element by proving that his presence was not voluntary.
Before we conclude that § 22-2511 im-permissibly shifts the burden of persuasion with respect to the element of voluntary presence, we must consider further whether the respective burdens of persuasion may coexist. ■ This depends on how we construe the government’s burden under subsection (a) to prove that the defendant “voluntarily” remained in the vehicle. If there are circumstances in which the government could prove beyond a reasonable doubt that the defendant “voluntarily” remained in the vehicle, yet the defendant could prove by a preponderance of the evidence that he would have left but had no reasonable opportunity to do so, then the respective burdens of persuasion would not be incompatible and there would not be an unconstitutional burden-shifting with respect to the element of voluntariness.
What is meant by the word “voluntarily” in subsection (a)? The word is “susceptible to different meanings,”36 so to answer that question, we must consider the statutory context and the purpose of the statute. As a matter of abstract logic, there is one possible interpretation of “voluntarily” that, if acceptable, would avoid the due process problem. If, to prove voluntariness, all the government needs to show is that it would have been physically possible for the defendant to leave the vehicle— regardless of the danger, difficulty, inconvenience, or adverse consequences of doing so, and however reluctantly the defendant chose not to leave in light of such impediments — then the affirmative defense would not be inconsistent with the government’s burden of persuasion. The respective burdens would be compatible because the government would simply have to prove that the defendant had an opportunity to leave, while the defense could prove that it was not a reasonable opportunity in the circumstances.
A hypothetical raised at oral argument in this case illustrates the distinction. Imagine' an elderly defendant who sees a gun in the center console of the vehicle she entered as a passenger but decides to stay in the vehicle until it is closer to a bus stop that is still a mile away because she has a bad knee. On such facts, the government could prove that the defendant “voluntarily” remained in the vehicle in the sense that she had an opportunity to leave it. But the defendant could prove that in light of her bad knee and consequent inability to walk a mile, the opportunity she had to exit the vehicle right away was not a reasonable opportunity.
Although this broad construction of the word “voluntarily” would manage to avoid the logical incompatibility of subsections (a) and (b), we are not persuaded that it is a plausible construction. No one, of course, can be held criminally liable “for failing to do an act that he is physically incapable of performing.”37 The word “voluntarily” would be superfluous if it was inserted in subsection (a) merely to make that basic jurisprudential point. The law [280]*280was not meant to target innocent persons like the elderly woman with the bad knee in the hypothetical, who remain unwillingly only because they have no reasonable opportunity to leave.38 Only in the most technical sense would one say of such a person that she “voluntarily” stayed in the car. In common parlance, we think one would say. she did not voluntarily remain.
Relatedly, a diffieult-to-accept consequence of construing the word “voluntarily” to mean only that the defendant had the physical ability to leave would be to increase the risk of convicting innocent defendants — persons who genuinely wanted to leave a vehicle containing a firearm but who had no reasonable opportunity to do so. That such persons would have the opportunity to avoid being convicted by proving the affirmative defense set forth in subsection (b) of the statute does not eliminate that risk, because shifting the burden of persuasion with respect to an essential element from the government to the defendant makes conviction more likely: There is a material difference between requiring the government to prove the existence of a reasonable opportunity to leave beyond a reasonable doubt in order to obtain a conviction and requiring the defendant to prove the absence of such an opportunity by a preponderance of the evidence in order to secure an acquittal. We do not lightly attribute to the Council the intent to increase the risk of convicting the innocent.39
Thus, we are persuaded that subsection (a) requires the government to prove beyond a reasonable doubt that the defendant forsook a reasonable opportunity to leave the vehicle; yet subsection (b) places the burden on the defendant to prove by a preponderance of the evidence that he had no such opportunity. The inconsistency is stark.40 We therefore are led to conclude that § 22-2511, read as a whole,41 unconstitutionally shifts the burden of persuasion from the prosecution to the defense with respect to voluntary presence, an essential element of the offense.
The government’s response to this conclusion is that we should sever the unconstitutional subsection (b). The general rule, as set forth in D.C.Code § 45-201(a) (2001), is that “the provisions of each act of the Council of the District of Columbia are deemed severable” unless the act in question expressly states otherwise (which § 22-2511 does not), so that the invalidity of a statutory provision “shall not affect other provisions ... of the act which can be given effect without the invalid provision.”42 This statutory directive would seem tó be applicable here: If we excise [281]*281the affirmative defense, the remaining provisions of § 22-2511 can be given effect consistently, in our view, with what the Council sought to achieve. And the pull of saving rather than destroying legislation when it is possible to avoid the latter is strong.43 If burden-shifting were the only constitutional problem with § 22-2511, we would opt to sever subsection (b), construe subsection (a) as indicated above, and save the statute in substantial part.
However, as we discuss next, there is another constitutional problem with § 22-2511 that we cannot cure by severance and interpretation. Even if the statute clearly required the government to prove that the defendant had a reasonable opportunity to leave the motor vehicle after learning that it contained a firearm but chose instead to stay, the statute still would be incompatible with the requirements of due process.
2. Criminalizing the Failure to Perform a Highly Unusual and Unforeseeable Duty
Even if § 22-2511 is construed to avoid an unconstitutional shifting of the burden of persuasion, appellant argues that the statute still violates due process because it creates an unusual legal duty previously unknown in the District of Columbia — the duty to leave a motor vehicle if it contains a firearm — without requiring proof that the defendant knew or should have known he had such a duty. As appellant recognizes, such proof ordinarily is not required; “[it] is a common maxim, familiar to all minds, that ignorance of the law will not excuse any person, either civilly or criminally....”44 In unusual circumstances, however, that maxim conflicts with “one of the bedrock principles of American law”: the principle that “[i]t is wrong to convict a person of a crime if he had no reason to believe that the act for which he was convicted was a crime, or even that it was wrongful.”45 Under such unusual circumstances, either the maxim or the principle must yield. In Lambert v. California,46 the case on which appellant principally relies, the Supreme Court confronted the question of when a legislature may impose criminal liability for failure to perform an unknown legal duty.
Lambert, like the present case, involved a crime of unlawful presence based on an obscure local enactment. A municipal ordinance made it unlawful for convicted felons “to be or remain” in Los Angeles for more than five days without registering with the police. Ms. Lambert, who had resided there for seven years, wás found guilty of having violated this ordinance by failing to register following her conviction in Los Angeles of forgery (a felony under California law). The state courts rejected her contention that the ordinance denied her due process of law because it neither required proof that the defendant’s failure to register was willful (i.e., that the defendant disregarded a known legal obligation to register) nor • recognized ignorance of the registration requirement as a defense.
The Supreme Court reversed Ms. Lambert’s conviction. The Court readily ac[282]*282knowledged that legislators have “wide latitude ... to declare an offense and to exclude elements of knowledge and diligence from its definition.”47 So too, the Court agreed, “[t]he rule that ‘ignorance of the law will not excuse’ is deep in our law, as is the principle that of all the powers of local government, the police power is ‘one of the least limitable.’ ”48 Nonetheless, the Court reasoned, the requirement of notice embodied in due process “places some limits” on the application of these tenets when a law criminalizes “conduct that is wholly passive ... [and] unlike the commission of acts, or the failure to act under circumstances that should alert the doer to the consequences of his deed.”49
The ordinance in Lambert met this description, as it made “mere presence” in the city unlawful in the complete absence of “circumstances which might move one to inquire as to the necessity of registra-tion_”50 Moreover, the Court noted, “this appellant on first becoming aware of her duty to register was given no opportunity to comply with the law and avoid its penalty, even though her default was entirely innocent.”51 To convict someone under such an ordinance, the Court held, due process requires the government to prove the defendant’s “actual knowledge of the duty to register or ... the probability of such knowledge and subsequent failure to comply....”52
As this court has stated, Lambert is “a rare instance” in which the Supreme Court has held that knowledge of the law is a constitutionally required prerequisite to criminal liability.53 While Lambert is not limited exclusively to registration statutes, it clearly does not stand for the proposition that ignorance of the law is a defense to every crime of omission, and it suggests “no general requirement that a State take [283]*283affirmative steps to inform its citizenry of their obligations under a particular statute before imposing legal sanctions for violation of that statute.”54 Rather, Lambert recognizes that “[t]he State’s power to impose sanctions on individuals is to be tested in part against the rationality of the proposition that those individuals were or could have been aware of their legal obligations.” 55 Lambert applies only when an unusual statute is “triggered in circumstances so commonplace, that an average citizen would have no reason to regard the triggering event as calling for a heightened awareness of one’s legal obligations.”56 In other words, only legal “duties of a highly unusual and unforeseeable nature” trigger Lambert,57 But when such novel and unanticipated duties are in question, it is no answer to say that the law is on the books, the books are in the public library, and anyone can go read them.58
Criminal laws seldom impose unusual and unforeseeable duties on the average person. In most cases in which courts have confronted the issue, they have found it fair to charge people with knowing their legal obligations because the circumstances put them on, at least, inquiry notice. Many of these cases inyolve “public welfare offenses” created by “statutes that regulate potentially harmful or injurious items” like drugs, highly dangerous weapons like machine guns and grenades, or noxious waste materials.59 In those cases, the Supreme Court has “reasoned that as long as a defendant knows that he is dealing with a dangerous device of a character that places him ‘in responsible relation to a public danger,’ he should be alerted to the probability of strict regulation, and [the Court has] assumed that in such cases Congress intended to place the burden on the defendant to ‘ascertain at his peril whether [his conduct] comes within the inhibition of the statute.’ ”60
This court has followed that reasoning. In McNeely, for instance, we rebuffed a [284]*284Lambert challenge to a provision of the “Pit Bull Act” making it a crime to own a pit bull that has injured or killed a human being or another domestic animal without provocation. We held that given the well-known dangerous proclivities of the breed, the owner’s “knowledge that his dogs were pit bulls should have moved him to inquire into his heightened obligations under the Act.”61 Similarly, in McIntosh v. Washington, we rejected a Lambert claim that the District’s firearms laws denied due process by imposing criminal penalties on those who fail to register their firearms, “regardless of their knowledge of the duty to register.”62 “[Wjhere dangerous or deleterious devices or products are involved,” we explained, “the probability of regulation is so great that anyone who is aware that he is either in possession of or dealing with them must be presumed to be aware of the regulation.”63
Courts also have rejected Lambert challenges to statutes imposing legal obligations on persons with other particular reasons to be on notice of them, as in prosecutions for violating 18 U.S.C. § 922(g)(9) and 18 U.S.C. § 922(g)(8) (statutes that prohibit the possession of firearms by persons who have been convicted of misdemeanor domestic violence offenses or who are subject to a judicial anti-harassment or anti-stalking order)64 and for failing to -register as required by the Sex Offender Registration and Notification Act (“SORNA”), 18 U.S.C. § 2250(a).65 (Judge Thompson’s concurrence cites a provision of the District’s old Narcotic Vagrancy statute (repealed in 1981) that, in a somewhat similar vein, made it a crime for “any person who is a narcotic drug user or who has been convicted of a narcotic offense” to be “found in any place ... in which any illicit narcotic drugs are kept, found used or dispensed.”66)
[285]*285The statute before us in this case, § 22-2511, is similar to the ordinance in Lambert:- It criminalizes the “wholly passive” state of “mere presence” in a particular location — a motor vehicle — without requiring proof of “actual knowledge” of a legal duty to absent oneself if the vehicle contains a firearm or “proof of the probability of such knowledge and subsequent failure to comply.”67 Nor does the statute require proof of any conduct beyond mere presence that would traditionally and fore-seeably subject a person to criminal sanction, such as handling or concealing the firearm, constructively possessing it, or aiding and abetting someone else’s possession or use of it. And it cannot be maintained (nor does the government contend) that penalizing mere presence is permissible because anyone who knowingly enters or stays in a car after learning it contains a gun must be embarked on a criminal venture of some sort. On the contrary, people harboring no evil intent of any kind may find themselves, inadvertently or otherwise, riding with a gun in a car, taxi cab, or truck for any number of innocent reasons — and, in doing so, they reasonably may perceive no necessity (let alone a legal obligation) to interrupt and discontinue their journey abruptly in order to make'a premature exit just because there is a gun present. Indeed, given the “long' tradition of widespread lawful gun ownership by private individuals in this country,”68 and the recent definitive recognition of a Second Amendment right to possess guns for self-protection,69 individuals (especially visitors from other jurisdictions) who do not happen to be well-versed in the intricacies of the District’s firearms laws may not see anything wrong in the presence of a gun or realize that the local law may proscribe its possession or transportation.70
Moreover, unlike § 22-2511, laws that survive Lambert challenges target those who are on inquiry notice of the legal duties imposed on them, by the nature of the activities in which they have chosen to engage. It is fair to say that persons who choose to own, possess, transport, or otherwise deal with firearms are or should be aware that their activities are highly regulated by law and that they must be alert to ascertain and comply with their attendant legal obligations. Such persons are on [286]*286notice that they may incur criminal penalties if they are not careful. But § 22-2511 requires no proof of firearm ownership, possession, transportation, or dealing by the defendant.71 The statute targets persons who. are not engaged in any of those activities and who therefore have no reason to be familiar with the'firearms, laws or to investigate whether those laws impose any duties on them. And the existence of § 22-2511, or any law regulating simple presence in the vicinity of a firearm, is certainly not common knowledge.
The critical question, then, is whether merely finding oneself riding in a motor vehicle with a gun is in itself a “circumstance[ ] which might move one to inquire as to the [legal] necessity” of exiting the vehicle;72 or, to put it more finely, whether the average person should know that he may be committing a felony offense merely by remaining in the vehicle, even if the gun belongs to someone else and he has nothing to do with it. We think not. Section 22-2511 is an anomaly, a unique departure from the fundamental and intuitive premise of our legal system that one does nothing wrong and does not become a criminal merely by being a bystander to a crime.73 It is a legal truism that, absent voluntary participation of some kind in criminal activity, “mere presence” in the vicinity of such activity is normally not culpable and is not subject to a criminal sanction.74 That proposition, we believe, [287]*287expresses a widely held expectation in our society — an expectation reinforced by the understanding that our Constitutional liberties include “the right to remove from one place to another according to one’s inclination”75 and the “individual’s decision to remain in a public place of his choice.”76 The freedom to move around as we see fit and be where we want to be with minimal legal constraint is indeed “part of our heritage.” 77
Statutes criminalizing trespass78 or knowing presence in an illegal establishment79 can be cited as exceptions to the generalization that “mere presence” is not a sufficient basis for criminal punishment.80 But the important point, for present purposes, is that those statutes raise no Lambert notice issue — the average citizen hardly would be unaware of the wrongfulness of trespassing or patronizing criminal enterprises,81 or surprised to learn of legal duties to avoid trespassing and frequenting illegal establishments. The PMVCF statute- is in a different category.
Indeed, the anomaly and unforeseeability of § 22-2511 are exacerbated by the peculiarity that it is only a crime to remain in the presence of a firearm when inside a motor vehicle. Nowhere else in the District of Columbia does one incur a legal duty to distance oneself upon learning of the presence of a gun on the premises or within one’s immediate proximity. Similarly, one who knows a friend is illegally carrying a firearm on his person may remain in the friend’s company all day long, pursuing a wide range of normal activities — for instance, walking on the street, going shopping, eating at a restaurant, seeing a movie, visiting the gym, conducting business, and so forth — without violating the law; yet under § 22-2511, if one takes the equally innocuous additional step of accompanying the friend in a car, truck, or bus, one suddenly and without warning commits a felony. Who, not previously [288]*288informed of it, would anticipate such a volte-face exception?
And to expand on a point made earlier, the duty created by § 22-2511 not to be in any motor vehicle containing a firearm is even more extraordinary and unimaginable because it is so unqualified — the existence of legitimate, innocent reasons for being in the vehicle voluntarily despite knowing that a firearm is present do not matter. Illustratively, the doctor who enters the ear to minister to a sick or injured occupant, the friend who drives that person to the hospital, the parent who seeks to take a child from the car, the person who desires only to retrieve his personal property from the vehicle — all are subject to § 22-2511; all are felons under the law if they act with knowledge that a firearm is in the vehicle. Again, who not previously informed of this statute would conceive of such a state of affairs?
Although, as Judge Thompson argues, motor vehicles are subject to “pervasive schemes of regulation,”82 we are aware of no vehicular regulation or regulatory scheme that would alert an innocent person to a legal duty to leave a vehicle if it contains a firearm. To say, for example, that passengers are on notice of regulations clearly connected to the consequences of their riding in a car — for example, regulations requiring them to wear seatbelts for their own protection in the event of an accident — does not imply they are legally responsible for the car’s contents (not their own) or put them on notice of a duty to leave a car depending on what objects happen to be in it. Few (if any) motor vehicle regulations impose duties on passengers based on the actions of other occupants. Similarly, we think it immaterial that (as the concurrence argues) motor vehicle passengers may be detained along with the driver in a traffic stop and, “if contraband is observed anywhere in the vehicle, may have them purses, backpacks, and similar containers searched.”83 That is true enough, but it is beside the point— it does not put innocent passengers on notice of the legal duty created by § 22-2511. The same is time of the self-evident fact, also mentioned in the concurrence, that the presence of a firearm increases the risk of harm if the motor vehicle is used to commit a crime.84
The average person surely does know that guns are dangerous and subject to regulation, and that while “guns generally can be owned in perfect innocence,”85 they also often are possessed illegally and used to commit crimes. In many circumstances, prudent, law-abiding persons naturally may be uncomfortable in the presence of firearms and wish not to be associated with them. Those facts are not enough, however, to put ordinary people on notice that merely being in a motor vehicle containing a gun is subject to the “strict regulation”86 that § 22-2511 imposes — that the simple sight of a handgun triggers a novel legal duty to leave a motor vehicle at once, or to refrain from entering one.
We are compelled to conclude that this case, like Lambert, presents the “rare
[289]*289instance”87 in which due process forbids the imposition of a criminal sanction unless the government is required to prove that the defendant had “actual knowledge” of the law or “the probability of such knowledge.” 88 By its terms, § 22-2511 does not require proof that the defendant knew it was a crime to enter or remain in a motor vehicle knowing it contains a firearm; there is no ambiguity in the statute that could be construed as requiring such proof. Because the statute therefore purports to allow the government, in every case, to obtain a conviction by proving only what cannot by itself be a crime, § 22-2511, as written, is facially unconstitutional.
We do not believe we properly can undertake to “cure” this facial defect by judicially decreeing that the statute means something other than what it says.89 As this court has stated on more than one occasion, “[i]t is not within the judicial function ... to rewrite the statute, or to supply omissions in it, in order to make it more fair.”90 Furthermore, this is not the more usual situation courts have faced in which a criminal statute that omits an intent element may be construed in light of “an interpretive presumption that mens rea is required.” 91 There is a difference between mens rea (as to which the statute is not silent) and knowledge of the law. There is no background presumption that a knowledge-of-the-law element is required by a criminal statute; au contraire, the starting point of our analysis has been “the well-established tenet that ignorance of the law [normally] is not a defense to criminal prosecution.” 92 Nor do we have warrant to infer a requirement that the government prove the defendant’s knowledge of the law in order to effectuate the goal of the statute. Adding such a requirement would thwart the Council’s intent to alleviate the government’s burden of proof. Of course, the Council remains free, if it wishes, to amend § 22-2511 so as avoid the constitutional defects we have identified.
As a result, we hold that § 22-2511 is unconstitutional on its face and that' the trial court erred in allowing appellant to be convicted of violating that statute. The first prong of plain error review is satisfied. We therefore proceed to consider the remaining requirements of plain error.
B. The Second, Third, and Fourth Prongs of Plain Error
For the error to be “plain,” it must be “clear under current law.”93 Our [290]*290discussion above shows that § 22-2511 runs afoul of fundamental principles of due process concerning fair notice and the government’s burden of proof that were settled long before appellant’s trial; indeed, long before § 22-2511 was enacted. The fact that the statute is such an anomaly, not only in the District of Columbia but in the entire United States, is a powerful indication that its unconstitutionality is clear. That there are few judicial precedents directly on point with respect to the Lambert issue speaks to the statute’s outlier status and does not preclude a finding of plain error, for “the ‘plainness’ of the error can depend on well-settled legal principles as much as well-settled legal precedents.”94 As we have said, “trial judges are presumed to know and apply the legal principles enunciated in appellate decisions, and not simply to match factual scenarios, as few cases present the same facts.”95 We conclude that the error in this case is plain.
The third and fourth requirements of plain error review also are met here. A felony conviction and a sentence of thirty-four months of incarceration for violating a facially unconstitutional statute are beyond doubt a serious infringement of appellant’s substantial rights and detrimental to the fairness and integrity of the judicial proceedings.
V.
Because D.C.Code § 22-2511 is unconstitutional on its face and the requirements of plain error review are satisfied, appellant’s conviction under that statute cannot stand. As appellant was acquitted of all the other offenses with which he was charged, we remand with directions that his conviction be vacated and that the charge of violating § 22-2511 be dismissed with prejudice.
So ordered.
Opinion by Associate Judge THOMPSON, concurring in the judgment.
8.This instruction mirrors Instruction 6.513 of the Criminal Jury Instructions for the District of Columbia (5th ed. Rev. 2010). In accordance with that model instruction, the judge further instructed the jury that:
A firearm may be lawfully carried outside the home only if a person [(a)] has a license to carry a pistol or is lawfully transporting a rifle or shotgun or ... [ (b) ] is a Government official authorized to carry a firearm.
A firearm may be lawfully transported only if it’s unloaded and either [ (a) ], [neither] the firearm nor ... the ammunition are readily or directly accessible from the passenger compartment of the transporting vehicle or [ (b) ], if the transporting vehicle does not have a compartment separate from the passenger’s compartment the firearm is in a locked container other than a glove compartment or console.