The Burden of Proving Insanity in the Medieval Ius commune

Abstract

The Burden of Proving Insanity in the Medieval Ius commune Brandon T. Parlopiano (bio) In 2006 the U.S. Supreme Court announced its ruling in the case of Clark v. Arizona.1 Michael Clark was charged with having knowingly committed the murder of a police officer, an offense that carries more severe punishment than simple murder under Arizona law. Clark was also diagnosed as schizophrenic, a condition witnesses testified was worsening in the weeks before the slaying. At trial, his legal counsel made a plea of insanity, a defense that Clark had the burden of proving under Arizona law. When the plea failed, the defense sought to introduce testimony that the state could not prove the requisite mens rea for the charge due to Clark's state of mental health. The presiding judge denied the admission of such testimony and subsequently found Clark guilty. The appeal eventually reached the Supreme Court, where the conviction was upheld. Among the myriad issues raised in Clark v. Arizona, one of the more salient was that of who bears the burden of proof in insanity defense cases. Is proof incumbent on the one alleging insanity, since it exists in most jurisdictions as an affirmative defense? Or is it incumbent on the prosecution, who has the obligation to prove all points of the charge, including a mens rea where applicable? The answers may vary from state to state, but most have enacted legislation laying the burden on those alleging insanity as a defense. The burden of proof became a contentious topic in American jurisprudence [End Page 515] as public outcry against the insanity defense grew stronger, particularly after the controversial 1982 acquittal of John Hinckley. The more recent case of Clark v. Arizona and the largely negative reaction it received show the issue to be just as problematic as ever.2 Our current legal trouble with mental illness is nothing new. As I will show, the jurists of the medieval ius commune, the system built on the foundations of Roman and canon law, sought answers to many of the same questions we are asking today. Such issues are now coming under increasing scrutiny by historians of the Middle Ages, especially those working in the emerging field of disability studies.3 In 2003, Catherine Kudlick succinctly provided a history of the advances made by disability studies and made a plea for historians to take it up as a category of analysis on par with gender, race, etc.4 Medieval legal studies, particularly of England, have benefitted from the pioneering work of Wendy Turner, among others.5 Still, the jurisprudence of the ius commune has received less attention. Given the emphasis of disability studies on uncovering the processes through which the identity of disability was negotiated, as well as the relevance to concerns in modern American law, I propose to chart the history of jurisprudential thought on the burden of proving insanity in the Middle Ages. Despite the extensive treatment of insanity's effects in Roman law, little evidence of how [End Page 516] the determination was made found its way into Justinian's codification.6 Medieval jurists, both canonists and civilians, constructed an original approach to the problem, incorporating both the principles taken from the libri legales as well as the demands of practice. Before moving into the juristic treatment of the burden of proof, I need to clarify two points basic to what follows. First, we need to ask where the proof for insanity fits within general conceptions of proof in the ius commune. The various forms proof could take came to be distinguished and graded by the jurists according to their relative strength in compelling the judge to pass sentence in one's favor.7 At the peak stood notoriety, that is, knowledge of a fact so certain that it precluded any contrary evidence; already in Gratian's analysis of due process, a notorium factum was sufficient to allow an abbreviated procedure.8 Included among notoria would be res iudicata, licit confessions, and even certain presumptions, such as the presumption of a valid marriage if sexual intercourse takes place on the condition of marriage.9 At a lower level, though still strong enough to...