Model Penal Code

The Model Penal Code (MPC) is one of the most important developments in American law, and perhaps the most important influence on American CRIMINAL LAW since it was completed in 1962. Conceived as a way to standardize and organize the often-fragmentary criminal codes enacted by the states, the MPC has influenced a large majority of states to change their laws. Although some provisions of the MPC are now considered outdated, and the code fails to address many important recent criminal law issues, its impact could still be felt as the country entered the twenty-first century.

Members of the American Law Institute (ALI), a group of judges, lawyers, and legal scholars whose purpose is to clarify and improve the law, began working on the Model Penal Code in 1952. The group had abandoned two previous attempts to create a model criminal code. The third attempt took ten years, and the ALI produced numerous drafts, reports, and revisions.

Herbert Wechsler, a Columbia Law School professor, served as the chief reporter, or principal drafter. From 1953 to 1962, ALI council members examined, considered, and debated the work of Wechsler, his staff, and his advisors in a total of 31 drafts. Finally, in 1962, the MPC was completed and published.

The impact of the MPC was immediate. For many states, the notion of codifying their criminal code was a foreign one—their criminal statutes were often poorly organized and did not define their crimes. The MPC arranged matters differently, organizing itself into four parts: (1) general provisions containing definitional functions and presumptive rules; (2) definitions of specific offenses; (3) provisions governing treatment and correction; and (4) provisions governing the organization of corrections departments and divisions such as the divisions responsible for PAROLE or PROBATION.

Several elements of the MPC have changed the way criminal law is administered in the United States. A good example of this is in the issue of mens rea, meaning state of mind or guilty mind. Previous state criminal statutes took a scattershot approach to mens rea, requiring it for some crimes and not for others, and using multiple terms to measure culpability. The MPC stated simply that a person is not guilty of an offense unless he or she acted purposely, knowingly, recklessly, or negligently, as the law may require, with respect to each material element of the offense. It then proceeded to define what these terms meant in a criminal law context, and what types of conduct would satisfy these terms. The clarity and simplicity of this approach made it desirable for many states to replace their codes with MPC-influenced codes. Following the introduction of the MPC, 36 states adopted new criminal codes, all of them influenced by the MPC and some of them using the exact language of the MPC for their statutes. Even if they did not adopt the language, some states used the MPC's model of organization as a starting point.

In addition, the MPC's influence is felt in the courts, where judges often rely on the code when handling substantive criminal law decisions. It has also become an important teaching tool in law schools, where the commentaries accompanying the code are read, as well as the code itself, in an attempt to gain insight into criminal law. Although the MPC has come under some criticism in recent years, with some critics suggesting that it may be time for revision, it remains firmly ensconced as an influence in the criminal laws of more than two-thirds of the states.