Thank you, XXXXX XXXXX I now understand the area of law you are discussing.
Strict liability offenses do require an actus reus, but they dispense with mens rea, or imply the necessary mens rea from the act.http://www.courts.ca.gov/partners/documents/calcrim_juryins.pdf
has the California criminal jury instructions, including this:
254. Union of Act and Intent: Strict-Liability Crime
For you to find a person guilty of the crime[s] of
<insert name[s] of alleged offense[s]> [or to find the allegation[s] of
<insert name[s] of enhancement[s]> true], a person
only needs to do the prohibited act [or to fail to do the required
act]. The People do not need to prove any intent or other mental
For a discussion of the rarity of strict-liability offenses
in modern criminal law, see People v. Garcia (2001) 25 Cal.4th 744, 754
[107 Cal.Rptr.2d 355, 23 P.3d 590], and People v. Simon (1995) 9 Cal.4th
493, 519–522 [37 Cal.Rptr.2d 278, 886 P.2d 1271].
P. v. Garcia, at page 754, states:
As we recently stated, "That the statute contains no reference to knowledge or other language of mens rea is not itself dispositive.... [T]he requirement that, for a criminal conviction, the prosecution prove some form of guilty intent, knowledge, or criminal negligence is of such long standing and so fundamental to our criminal law that penal statutes will often be construed to contain such an element despite their failure expressly to state it. 'Generally, " '[t]he existence of a mens rea is the rule of, rather than the exception to, the principles of Anglo-American criminal jurisprudence.' ..." (People v. Simon[, supra,] 9 Cal.4th 493, 519 ..., citations omitted.) In other words, there must be a union of act and wrongful intent, or criminal negligence. (Pen. Code, § 20; People v. Vogel (1956) 46 Cal.2d 798, 801 [299 P.2d 850].) "So basic is this requirement that it is an invariable element of every crime unless excluded expressly or by necessary implication." (People v. Vogel, supra, at p. 801, fn. omitted.)' (People v. Coria (1999) 21 Cal.4th 868, 876 [89 Cal.Rptr.2d 650, 985 P.2d 970].)" (In re Jorge M., supra, 23 Cal.4th at p. 872.)
P. v. Coria, posted athttp://login.findlaw.com/scripts/callaw?dest=ca/cal4th/21/868.html
On appeal, defendant contends the trial court erred in instructing the jury that, to be guilty of manufacturing methamphetamine in violation of section 11379.6, subdivision (a), it was not necessary for defendant to have been aware it was methamphetamine that was being manufactured via the extraction process.
This instruction was derived from People v. Telfer[[, supra,]] 233 Cal.App.3d 1194 [284 Cal.Rptr. 913], which held that manufacturing of methamphetamine is a strict liability offense, i.e., knowledge of the physical character of the substance being manufactured is not an element of the offense and, "[s]o long as the product of the defendant's activity was methamphetamine ..., the defendant is guilty, even if he did not know that methamphetamine would be that product." (Id., at p. 1204.)
For reasons that follow, we disagree with the reasoning of People v. Telfer, supra, 233 Cal.App.3d 1194, which analogized section 11379.6 to strict liability "public welfare" statutes that generally are regulatory in nature, impose light penalties, have little "damage to reputation," and thus have no mens rea requirement. As we shall explain, the crime of manufacturing methamphetamine-a felony punishable by incarceration in state prison-must be interpreted to include as an element of the offense the accused's knowledge of the character of the substance being manufactured. Hence, the trial court's instruction to the contrary was erroneous. As the error was prejudicial, we shall reverse the judgment.
Defendant contends the trial court erred in giving this portion of the instruction, thereby incorrectly converting section 11379.6 into a strict liability crime. He argues it would be anomalous to permit him to be convicted of manufacturing methamphetamine if he did not know methamphetamine was being manufactured, when, absent knowledge of the character of the substance, he could not be convicted of possessing the contraband resulting from the manufacturing process. We agree.
 In a prosecution for possession of a controlled substance, knowledge of the character of the substance possessed is an essential element of the [21 Cal.4th 875] crime. (People v. Williams (1971) 5 Cal.3d 211, 215 95 Cal.Rptr. 530, 485 P.2d 1146]; People v. Winston (1956) 46 Cal.2d 151, 161 [293 P.2d 40].) The requirement that the accused be aware of the character of the substance also applies to crimes of selling or transporting a controlled substance (People v. Daniels (1975) 14 Cal.3d 857, 860 [122 Cal.Rptr. 872, 537 P.2d 1232]; People v. Rogers (1971) 5 Cal.3d 129, 133, 137 [95 Cal.Rptr. 601, 486 P.2d 129]), and to the crime of cultivating marijuana (People v. Gorg (1955) 45 Cal.2d 776, 780 [291 P.2d 469]).
 Generally, " '[t]he existence of a mens rea is the rule of, rather than the exception to, the principles of Anglo-American criminal jurisprudence.' ..." (People v. Simon (1995) 9 Cal.4th 493, 519 [37 Cal.Rptr.2d 278, 886 P.2d 1271], citations omitted.) In other words, there must be a union of act and wrongful intent, or criminal negligence. (Pen. Code, § 20; People v. Vogel (1956) 46 Cal.2d 798, 801 [299 P.2d 850].) "So basic is this requirement that it is an invariable element of every crime unless excluded expressly or by necessary implication." (People v. Vogel, supra, at p. 801, fn. omitted.) In addition, Penal Code section 26 provides that a person is incapable of committing a crime where an act is performed in ignorance or mistake of fact negating criminal intent; a crime cannot be committed by mere misfortune or accident. (People v. Lopez (1986) 188 Cal.App.3d 592, 597 [233 Cal.Rptr. 207].)
 There is an exception to the mens rea requirement for certain so-called public welfare crimes. Such offenses generally are based upon the violation of statutes which are purely regulatory in nature and involve widespread injury to the public. (People v. Matthews (1992) 7 Cal.App.4th 1052, 1057-1058 [9 Cal.Rptr.2d 348].) "Under many statutes enacted for the protection of the public health and safety, e.g., traffic and food and drug [21 Cal.4th 877] regulations, criminal sanctions are relied upon even if there is no wrongful intent. These offenses usually involve light penalties and no moral obloquy or damage to reputation. Although criminal sanctions are relied upon, the primary purpose of the statutes is regulation rather than punishment or correction. The offenses are not crimes in the orthodox sense, and wrongful intent is not required in the interest of enforcement." (People v. Vogel, supra, "46 Cal.2d at p. 801, fn. 2.)
The United States Supreme Court has emphasized that felony offenses which bear harsh punishment are not the type of "public welfare" offenses for which courts will readily dispense with the mens rea requirement when construing a statute. (Staples v. United States, supra, 511 U.S. at pp. 616-617 [114 S.Ct. at pp. 1802-1803, 128 L.Ed.2d at pp. 623-624]; People v. Simon, supra, 9 Cal.4th at p. 520[[, fn. 17]].)
The opinion goes on to cite Staples v. United States (92-1441), 511 U.S. 600 (1994) in analyzing when mens rea is not required. Staples is posted athttp://www.law.cornell.edu/supct/html/92-1441.ZO.html
The Staples opinion states:
we must construe the statute in light of the background rules of the common law, see United States v. United States Gypsum Co., 438 U.S. 422, 436-437 (1978), in which the requirement of some mens rea for a crime is firmly embedded. As we have observed, "[t]he existence of a mens rea is the rule of, rather than the exception to, the principles of Anglo American criminal jurisprudence." Id., at 436 (internal quotation marks omitted). See also Morissette v. United States, 342 U.S. 246, 250 (1952) ("The contention that an injury can amount to a crime only when inflicted by intention is no provincial or transient notion. It is as universal and persistent in mature systems of law as belief in freedom of the human will and a consequent ability and duty of the normal individual to choose between good and evil").
There can be no doubt that this established concept has influenced our interpretation of criminal statutes. Indeed, we have noted that the common law rule requiring mens rea has been "followed in regard to statutory crimes even where the statutory definition did not in terms include it." Balint, supra, at 251-252. Relying on the strength of the traditional rule, we have stated that offenses that require no mens rea generally are disfavored, Liparota, supra, at 426, and have suggested that some indication of congressional intent, express or implied, is required to dispense with mens rea as an element of a crime. Cf. United States Gypsum, supra, at 438; Morissette, supra, at 263.
Such public welfare offenses have been created by Congress, and recognized by this Court, in "limited circumstances." United States Gypsum, 438 U. S., at 437. Typically, our cases recognizing such offenses involve statutes that regulate potentially harmful or injurious items. Cf. United States v. International Minerals & Chemical Corp., 402 U.S. 558, 564-565 (1971) (characterizing Balint and similar cases as involving statutes regulating "dangerous or deleterious devices or products or obnoxious waste materials"). In such situations, we have 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," Dotterweich, supra, at 281, he should be alerted to the probability of strict regulation, and we have 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." Balint, supra, at 254. Thus, we essentially have relied on the nature of the statute and the particular character of the items regulated to determine whether congressional silence concerning the mental element of the offense should be interpreted as dispensing with conventional mens rea requirements. See generally Morissette, supra, at 252-260. [n.3]
Here, there can be little doubt that, as in Liparota, the Government's construction of the statute potentially would impose criminal sanctions on a class of persons whose mental state--ignorance of the characteristics of weapons in their possession--makes their actions entirely innocent.
The potentially harsh penalty attached to violation of § 5861(d)--up to 10 years' imprisonment--confirms our reading of the Act. Historically, the penalty imposed under a statute has been a significant consideration in determining whether the statute should be construed as dispensing with mens rea. Certainly, the cases that first defined the concept of the public welfare offense almost uniformly involved statutes that provided for only light penalties such as fines or short jail sentences, not imprisonment in the state penitentiary. See, e. g., Commonwealth v. Raymond, 97 Mass. 567 (1867) (fine of up to $200 or six months in jail, or both); Commonwealth v. Farren, 91 Mass. 489 (1864) (fine); People v. Snowberger, 113 Mich. 86, 71 N. W. 497 (1897) (fine of up to $500 or incarceration in county jail). [n.12]
As commentators have pointed out, the small penalties attached to such offenses logically complemented the absence of a mens rea requirement: in a system that generally requires a "vicious will" to establish a crime, 4 W. Blackstone, Commentaries *21, imposing severe punishments for offenses that require no mens rea would seem incongruous. See Sayre, Public Welfare Offenses, 33 Colum. L. Rev. 55, 70 (1933). Indeed, some courts justified the absence of mens rea in part on the basis that the offenses did not bear the same punishments as "infamous crimes," Tenement House Dept. v. McDevitt, 215 N. Y. 160, 168, 109 N. E. 88, 90 (1915) (Cardozo, J.), and questioned whether imprisonment was compatible with the reduced culpability required for such regulatory offenses. See, e. g., People ex rel. Price v. Sheffield Farms Slawson Decker Co., 225 N. Y. 25, 32-33, 121 N.E. 474, 477 (1918) (Cardozo, J.); id., at 35, 121 N. E., at 478 (Crane, J., concurring) (arguing that imprisonment for a crime that requires no mens rea would stretch the law regarding acts mala prohibita beyond its limitations). [n.13] Similarly, commentators collecting the early cases have argued that offenses punishable by imprisonment cannot be understood to be public welfare offenses, but must require mens rea. See R. Perkins, Criminal Law 793-798 (2d ed. 1969) (suggesting that the penalty should be the starting point in determining whether a statute describes a public welfare offense); Sayre, supra, at 72 ("Crimes punishable with prison sentences . . . ordinarily require proof of a guilty intent"). [n.14]
In rehearsing the characteristics of the public welfare offense, we, too, have included in our consideration the punishments imposed and have noted that "penalties commonly are relatively small, and conviction does no grave damage to an offender's reputation." Morissette, 342 U. S., at 256. [n.15] We have even recognized that it was "nder such considerations" that courts have construed statutes to dispense with mens rea. Ibid.
Our characterization of the public welfare offense in Morissette hardly seems apt, however, for a crime that is a felony, as is violation of § 5861(d). [n.16] After all, "felony" is, as we noted in distinguishing certain common law crimes from public welfare offenses, " `as bad a word as you can give to man or thing.' " Morissette, supra, at 260 (quoting 2 F. Pollock & F. Maitland, History of English Law 465 (2d ed. 1899)). Close adherence to the early cases described above might suggest that punishing a violation as a felony is simply incompatible with the theory of the public welfare offense. In this view, absent a clear statement from Congress that mens rea is not required, we should not apply the public welfare offense rationale to interpret any statute defining a felony offense as dispensing with mens rea. But see Balint, supra.
We need not adopt such a definitive rule of construction to decide this case, however. Instead, we note only that where, as here, dispensing with mens rea would require the defendant to have knowledge only of traditionally lawful conduct, a severe penalty is a further factor tending to suggest that Congress did not intend to eliminate a mens rea requirement. In such a case, the usual presumption that a defendant must know the facts that make his conduct illegal should apply.
So my answer is Yes, there are constitutional issues with strict liability offenses, as illustrated in the authorities cited above.
I hope this information is helpful.