Penal Code section 12280, subdivision (b), which criminalizes the possession of an assault weapon, was not intended to define a strict liability offense. However, actual knowledge of the weapon’s prohibited characteristics is not necessarily required. A conviction may be upheld upon proof of a negligent failure to know, as well as knowledge of, the weapon’s characteristics which bring it within the registration requirements of the Assault Weapons Control Act (AWCA). Here, the Court of Appeal had reversed appellant’s conviction for a violation of section 12280, subdivision (b), because the record contained insufficient evidence that the minor knew the firearm was prohibited by the AWCA, relying heavily on the authority of Staples v. United States (1994) 511 U.S. 600. The Supreme Court reversed the decision of the Court of Appeal. The statute itself contains no reference to knowledge or other language of mens rea. However, the offense cannot be categorized as a public welfare offense for which the Legislature intended guilt without proof of mental state, as assault weapons have a lawful use, and only specific assault weapons are prohibited, which are not so readily discernible that innocent possession would be unlikely. A construction of section 12280, subdivision (b), which dispenses completely with scienter, would result in the severe punishment of innocent possessors, a result which was not intended by the Legislature. Although an actual knowledge requirement might impede law enforcement, a scienter requirement satisfied by the proof that the defendant should have known the characteristics of the weapon bringing it within the AWCA, would not do so, and would be sufficient to protect the innocent from punishment. Here, under that standard, there was sufficient evidence from which to conclude that the minor should have known about the weapon’s salient characteristics. The words “Russia SKS-45” was printed on the side of the weapon, and the magazine was detachable. Therefore the minor should have known that the weapon was an “SKS with detachable magazine” as proscribed by the AWCA, and his conviction should have been upheld. J. Kennard dissented, holding that actual knowledge should be an element of the offense. The majority’s test casts “too wide a net,” snaring persons without the culpability necessary for a state prison sentence.