To understand the impact of clearly defining criminal conduct, one can look to the days when crimes were not defined so carefully. Back in the days of merry olde England, not too long after the last millennium, it was pretty easy to run afoul of the law, which was vague at best. If you did something that the church, the King or the nobles didn't like, you would usually be made to suffer dreadfully. However, after the Magna Carta was signed in 1215, the concept began to take hold that you should only be punished if you committed a defined crime, as did the concept that trial by a judge or jury was more appropriate than trial by torture. Even then, if you were found guilty of a crime, death was often the punishment as well as forfeiture of your property. For especially heinous crimes, execution was accompanied by especially heinous treatments, such as the fabled drawing and quartering.

As more and more cases found their way into the English courts, the courts began to honor what previous courts had done in similar cases. This development gave rise to what is known as "precedent." One of the hallmarks of precedent was that it need be applied only if the later case involved the same or very similar facts as the earlier case. This fact allowed judges to use the individual facts of the case before them to distinguish that case from the earlier case and therefore do justice on an individual basis. In other words, over time, the law began to stretch. Individual cases cried out for different treatment than previous cases, often because they were in fact different.

For instance, assume that a person accused of stealing was an otherwise honest person driven to his deed by dire family circumstances. If the judge in that case followed the law of the time, death might well have been the mandatory punishment. However, if the judge could somehow redefine the defendant's actions so that the defendant wasn't guilty of stealing after all, he wouldn't have to sentence the poor fellow to the gallows.