Does the Magna Carta Embody a Proportionality Principle?


American scholars often argue that the Magna Carta embodies a “proportionality principle” mandating that the punishment fit the crime. This principle, according to a familiar narrative, found expression centuries later in the English Bill of Rights, which was reproduced another century later in the American Bill of Rights. Justices on the U.S. Supreme Court have claimed the authority of the Magna Carta when infusing the Eighth Amendment with a proportionality principle not immediately evident from its text. 

This Essay explores and questions the narrative. The argument that the Magna Carta embodies a proportionality principle seizes upon three Chapters (20 to 22) that provide that a penalty not exceed “the degree of the offense.” Yet these sections exclusively concern the Norman practice of amercements—a penalty imposed for a litany of administrative offenses that were almost never of a criminal nature. Furthermore, given the prevalence of violent crime and the widespread acceptance of cruel punishment, it is implausible to project humanitarian motives onto the authors of Chapters 20 to 22. The Essay concludes with broader reflections on the uses made of the Magna Carta in this year, the 800th anniversary of its sealing.  Like virtually every legal document in recorded history, the Magna Carta embodies at some level a proportionality principle. But as jurists purport to extract more meaningful and specific lessons from the Magna Carta on this and other points, their arguments lapse into poor scholarship and hopeless anachronism.