Mistake

However, a problem surfaces at this point. Under the Model Penal Code and the approaches of most commentators, mistakes as to the meaning or existence of the criminal statute under which one is punished do not exculpate, whereas other mistakes of both law and fact may. But how is the line between these types of mistakes to be drawn? A legal positivist will regard law and its meaning as a species of fact. Whether there is a law against rape will depend upon facts about the legislature (whose existence and powers are themselves the product of other facts)—what it enacted, and so on—and the meaning of that law will depend upon facts about complex linguistic and judicial practices.

Moreover, at least for purposes of the criminal law, the proper jurisprudential stance arguably must be positivism: the principle of legality (i.e., that criminal laws must be enacted prior to the conduct they criminalize) and its corollary principle against vagueness can be viewed as demanding that the existence and meaning of criminal statutes be accessible to those subject to them in the manner that only facts, not values, can be.

Now what facts constitute the existence or meaning of the criminal law, mistakes as to which do not excuse, as opposed to those other facts, mistakes as to which do excuse? Let us consider some variations on the well-known hypothetical case of Lady Eldon, who returns to England from a visit to France with some French lace that she has purchased in her luggage. When asked at customs if she has any dutiable items to declare, she replies "no." French lace is a dutiable item. Has Lady Eldon committed a crime? (Wharton, p. 304). See F. Wharton, Criminal Law (1932): 304 n.9. (In the actual hypothetical, Lady Eldon's mistake is inculpatory, not exculpatory.)

Consider two variants of this hypothetical case. In the first variant, there is a law against failing to declare dutiable items. Those items are listed in regulations that are changed from time to time. Lady Eldon mistakenly believes French lace has been taken off the list. In the second variant, the criminal law itself states "it is a crime to fail to declare . . . French lace." Lady Eldon mistakenly believes that there is no such crime. In the latter case it seems clear that she has made a mistake about the existence and meaning of the criminal law. But how is this case different in any material way from the former? Moreover, suppose she had read the regulations in the former case and misperceived the word "French" as "Flemish." How would that mistake be any different from, say, her perceiving the lace she is carrying as Flemish lace rather than as French lace, a mistake that would exculpate her if the statute requires a mental state of purpose, knowledge, or recklessness with respect to whether the lace one is failing to declare is French lace? Both mistakes are "factual."

Several approaches are taken to defining the boundary between those mistakes of law that do not excuse (except under rarefied conditions) and those mistakes of both law and fact that can excuse. The problem is usually formulated as distinguishing those mistakes of law that relate to the existence or meaning of the criminal statute and those mistakes of law that do not, with mistakes of fact being a third and nonproblematic kind of mistake. Because all mistakes of law are particular kinds of mistakes of fact, all three kinds of mistake are capable of collapsing into one another. But even if we accept that ordinary mistakes of fact are nonproblematic—they clearly can negate criminal liability by negating a required mental state—drawing the boundary between those mistakes of law that can negate criminal liability and those that rarely do is surely difficult conceptually.

Some identify the distinction as one between mistakes regarding the law under which one is prosecuted ("same law" mistakes) and mistakes regarding other laws ("different law" mistakes). Examples to illustrate the distinction include prosecution under a bigamy statute of one who knew about the proscription of bigamy but mistakenly believed his divorce from his first wife was legally valid; and prosecution under a theft statute of one who drives her car away from a garage after refusing to pay the mechanic what she regards as an excessive bill without realizing that under the law, the mechanic has a possessory lien on the car until the bill is paid; and the case in which defendant, unaware that under the law of property, the paneling he had put in his apartment had become the property of his landlord, tore up the paneling and was prosecuted for destroying the property of another.

The same law/different law approach requires that we have a theory about how to individuate laws. But no one has offered such a theory. Moreover, the prospects of coming up with one are bleak. How one individuates laws—for example, whether one considers the law of property, including the law regarding mechanics' liens or emblements, as separate from or as part of the law of theft or the law of destruction of others' property—looks to be quite arbitrary in the abstract without identifying the principles and policies that motivate the individuation. For example, different degrees of culpability might attach to different legal mistakes, though it is doubtful that differences in culpability will be consistent enough to make clear seams of individuation within the otherwise seamless web of the law.

The same criticism applies to other attempts to differentiate those mistakes of law that almost never negate criminal liability from those that frequently do. Some identify the distinction as one between mistakes of criminal law and mistakes of civil law. But mistakes of criminal law can be exculpatory when one criminal law refers to another. For example, conviction under a law criminalizing knowingly receiving stolen property can be defeated by the defendant's mistake, not as to the existence of that law, but as to whether the property he received is stolen. That mistake is one of criminal law.

Another proposed solution is to distinguish mistakes of law that relate to elements of a criminal offense and mistakes of law that relate to the existence and meaning of the criminal law governing the transaction. But this elements/governing-law distinction between mistakes of law requires that we be able to distinguish between the meaning of a criminal law and the meaning of its elements.