Here are the facts from the majority opinion of the Pennsylvania Supreme Court in Commonwealth of Pennsylvania v. Noel:
On April 7, 2002, the Pennsylvania State Police stopped Appellees Richard Carroll Noel and Keith Douglas Travis while they were riding horses on a public highway in Springfield Township, Mercer County because they appeared to be intoxicated. Appellees were subsequently charged with Driving While Under the Influence of Alcohol ("DUI").
The relevant part of the Pennsylvania Motor Vehicle Code states as follows:
Every person riding an animal or driving any animal-drawn vehicle upon a roadway shall be granted all of the rights and shall be subject to all of the duties applicable to the driver of a vehicle by this part, except those provisions of this part which by their very nature can have no application or where specifically provided otherwise.
The defense argued that "by their very nature" the DUI provisions did not apply to horseback riders. The trial court stated that it could not clearly determine what provisions "by their very nature" did not apply to horseback riders and, therefore, the statute is unconstitutionally vague in violation of the due process clause.
I like this case for class for two reasons. First, it is a "two-fer." The case is a natural to illustrate two legal principles. I use it to explain the requirement under substantive due process that a criminal statute must give unambiguous "fair warning" of the conduct that has been criminalized. I also use it to explain the need for statutory interpretation by courts. As is often the case, a statute which seems reasonably clearly written when read in a vaccuum, becomes noticeably ambiguous when applied to a challenging set of facts. Therefore, the court's interpretation is necessary.
Second, there is an witty dissent in the case written by Mr. Justice Eakin. After opening his opinion by quoting the theme song to Mr. Ed, a 1960's sitcom about a talking horse, Justice Eakin summarizes his rationale by composing it to the Mr. Ed theme. (Here is another link to the dissent.)
Here is a short clip to illustrate to your students the premise of the show, Mr. Ed:
Here is the Mr. Ed theme song:
And here is the excerpt from Mr. Justice Eakin's dissent set to music: