warning–then the public should be able to ascertain the line between permitted and prohibited conduct 
from the statute itself.” 
12 
Third, judges may try to focus on the original understanding or original meaning of the law. Under this 
approach, the court asks itself how a common person reading the law when it was enacted, would have 
understood the law. For example, when looking at a statute written in 1972, the court would ask itself how 
the common person in 1972 would have understood the statute. This approach is problematic because not 
all people living in 1972 would have interpreted the law in the same way. 
Fourth, as discussed above, judges may interpret the law based on precedent. One drawback to this 
approach is that facts of the earlier cases will always differ somewhat from the facts in the new case the 
court is trying to interpret. Another difficulty occurs when the court is faced with a new situation or a new 
law and there is no precedent to guide the court. LaFave identified the difficulty in adhering too closely to 
precedent: 
“Sometimes a court, having earlier construed a criminal statute strictly in favor of the defendant, later 
decides that its earlier construction was wrong. … Obviously, other things being equal, courts should 
interpret statutes correctly, regardless of past mistakes. On the other hand, it may not be fair to . . . 
change the rule now. The difficulty lies in the Anglo-American theory of precedents that case law operates 
retroactively, and in particular that case law which overrules earlier precedents operates retroactively. 
When faced with this problem–that of overruling or following an earlier erroneous interpretation . . . [one] 
court felt obliged to follow case precedent with an invitation to the legislature to change the rule of for the 
future; but [another court overruled the precedent.] 
The choice, however, is not necessarily between following the precedent (thus letting a defendant off 
but perpetuating a bad decision) and retroactively overruling it (thus eliminating a bad precedent but 
putting the defendant behind bars). There are two techniques by which the defendant may go free even 
if the precedent is overruled. It is not impossible for the court to overrule for the future only, letting the 
defendant go but stating in the opinion that anyone who from now on conducts himself the way this 
defendant did will be guilty of the crime. The second method is to overrule the erroneous precedent but 
to give the defendant the defense of mistake of law induced by an appellate court. … Some courts have 
gone so far as to say that the adoption of a new interpretation of an old statute is forbidden by ex post facto 
constitutional provision if the new interpretation is harder on the defendant than the old.” 
13 
Finally, there are common law doctrines which direct the court to interpret ambiguous terms in a 
specific way. For example, the rule of lenity tells the court to interpret the statute in the light that is most 
favorable to the defendant. Another rule, expressio unius est exclusion alters, meaning the inclusion of one is 
the exclusion of all others, holds that when a legislative body includes specific items within a statute, the 
assumption is that it intends to exclude all other terms. Another doctrine of in pari materia, meaning on the 
same matter or subject, directs the court to interpret an ambiguous statute in a light most consistent with 
12. LaFave, W. R. (2000). Criminal law (3rd ed., pp. 89). St. Paul, Minn: West Group. 
13. LaFave, W. R. (2000). Criminal law (3rd ed., pp. 96-97). St. Paul, Minn: West Group. 
ALISON S. BURKE, DAVID CARTER, BRIAN FEDOREK, TIFFANY MOREY, LORE RUTZ-BURRI, AND SHANELL
SANCHEZ
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