INTRODUCTION: THE NATURE OF THE PROBLEM
The criminal law is rife with old saws. (1) For example, there is the tenet that there can be no crime or criminal punishment without a positive law, known in Latin as "Nullum crimen sine lege" and "Nulla poena sine lege." (2) Another such proposition is that a crime consists of "a vicious will" and "an unlawful act consequent upon such vicious will." (3) Also widely known are the principles that every person is entitled to a presumption of innocence (4) and that it is the government's burden to rebut that presumption beyond a reasonable doubt. (5) Another maxim, the lex talionis, is "An eye for an eye, a tooth for a tooth," (6) which can be rephrased as "The punishment should fit the crime." And there is the well-known saying, drawn from the Bible, (7) that "It is better that ten guilty men go free than that one innocent man be convicted." (8) Finally, an old criminal law proverb is the proposition that "Ignorance of the law is no excuse," which sometimes is phrased as a rule of evidence that "Every man is presumed to know the law." (9)
The ignorance-of-the-law rule traces its lineage back to Roman law. (10) The English common law courts adopted the rule, (11) from whence it came to America. In this country, state (12) and federal courts, (13) including the Supreme Court of the United States, (14) as well as criminal law treatise writers, (15) have long endorsed that rule. The proposition that ignorance or mistake of the law is no excuse therefore has an ancient pedigree.
Most rules of law that have survived that long have a fairly robust justification, even if it is not the same one that gave birth to the rule. (16) Moreover, criminal justice principles repeatedly and recently championed by the Supreme Court have the highest precedential value. (17) The rule that mistake of law is no excuse fits into that category.
An ancient pedigree for a rule, however, does not guarantee that the rule still makes sense and therefore should not serve to defeat all efforts at reexamination. The rules that govern society today must make sense today, whatever their merit long ago. Law is the formal recognition of the mores and values of a society and should be adjusted to fit whatever changes society deems necessary. Sometimes that adjustment cannot be done without revisiting, reshaping, or abandoning law on the statute books or in the case reports. When that happens, the society is better off by altering the law to fit current...