Model Penal Code (MPC)
The Model Penal Code (MPC) was developed as a guideline to assist the divers legal jurisdictions in the United States standardize their criminal law procedure according to "contemporary reasoned judgment." Because of the great legislative and judicial independence entrusted to the states and municipalities of the U.S., the legal landscape has naturally become extremely varied in this country over time. By the middle of the last century, this diversity had become so extreme that in 1962 the American Legal Institute codified the Model Penal Code in an attempt to inspire some uniformity. It was last updated in 1981.
Even though the MPC is a statutory work, no jurisdiction is required to adhere to its guidelines. It recommends only. As of 2007, thirty-seven states have adopted modified and partial versions of the Model Penal Code and several, including New York, New Jersey and Oregon, have enacted nearly all of its provisions.
The Model Penal Code is broad and expansive, but one of its most important features is the clarification of criminal intent. Mens rea, perhaps the most important element of criminal activity considered in trials while determining the nature of a crime and its just punishment, is standardized into four simple terms in the Model Penal Code. Crimes are said to be committed Purposefully, Knowingly, Recklessly and Negligently, with the first two constituting a more serious "intentional" classification and the second two a less serious "unintentional" classification. This is one of the most commonly enacted provisions of the MPC, since it elegantly simplifies the very sticky notion of guilty mental states in criminal law.
Another vital feature of the Model Penal Code is its recommendation that any activity not explicitely forbidden by the law is legal. This is meant to contrast the legal systems of the Third Reich and the USSR, which allowed for its citizens to be punished for activities not explicitly forbidden by the law but similar to activities that were. "Anything not forbidden is legal," rather than "anything not legalized is forbidden" is the message reinforced by the MPC, a precept most fitting for a free and democratic society.