IN APPROXIMATELY HALF OF THE STATES, ASSERTION OF THE INSANITY DEFENSE DOES NOT AFFECT THE PROSECUTION'S BURDEN OF PERSUASION. IN OTHER STATES, A DEFENDANT WHO RAISES THE INSANITY DEFENSE MUST PROVE THAT HE WAS INSANE AT THE TIME OF THE ALLEGED CRIME. THESE STATES REQUIRE THAT THE DEFENDANT PROVE INSANITY ONLY BY A PREPONDERANCE OF THE EVIDENCE. IN MULLANEY V. WILBUR, THE U.S. SUPREME COURT FOUND UNCONSTITUTIONAL A STATE LAW REQUIRING DEFENDANTS TO PROVE TO A PREPONDERANCE OF THE EVIDENCE THAT THEY HAVE ACTED IN THE HEAT OF PASSION ON SUDDEN PROVOCATION. FOCUSING ON THE ELEMENTS OF THE CRIME CHARGED, THE COURT FOUND THAT THE BURDEN ALLOCATION VIOLATED DUE PROCESS. THE COURT USED THE INTERESTS APPROACH, WEIGHING THE DEFENDANT'S INTEREST IN THE OUTCOME OF THE TRIAL AND THE INTERESTS OF THE COMMUNITY IN THAT OUTCOME, TO JUSTIFY IMPOSING ON THE PROSECUTION THE BURDEN OF PERSUASION BEYOND A REASONABLE DOUBT. THE DECISION CASTS DOUBT ON THE VALIDITY OF STANDARDS THAT SHIFT THE BURDEN OF PERSUASION TO THE DEFENDANT ON THE INSANITY ISSUE AND REQUIRE THE BURDEN TO BE CARRIED ONLY TO THE PREPONDERANCE OF THE EVIDENCE. IT IS ARGUED THAT DUE PROCESS IS BEST PROTECTED BY EXTENDING THE MULANEY FINDING TO THE INSANITY DEFENSE. THE PROSECUTION SHOULD CARRY THE BURDEN OF PERSUASION ON THE INSANITY DEFENSE BEYOND A REASONABLE DOUBT UNTIL AN EXACTING STANDARD IS FORMULATED. PAST APPROACHES USED BY THE SUPREME COURT TO EXAMINE THE ALLOCATION OF THE BURDEN OF PERSUASION ARE CRITICIZED, AS IS AN ATTEMPT TO DEVISE AN EXACTING STANDARD TO JUSTIFY SHIFTING THE BURDEN.