DISCUSSED IS THE SUPREME COURT DECISION IN MULLANEY V. WILBUR (1975), IN WHICH THE COURT HELD THAT THE DUE PROCESS CLAUSE OF THE FOURTEENTH AMENDMENT REQUIRES THE PROSECUTION TO PROVE BEYOND A REASONABLE DOUBT THE ABSENCE OF HEAT OF PASSION ON SUDDEN PROVOCATION IN A HOMICIDE CASE WHEN THE ISSUE IS PROPERLY PRESENTED THE COURT REJECTED THE STATE OF MAINE'S ARGUMENT THAT THE ISSUE OF HEAT OF PASSION DID NOT ARISE UNTIL ALL THE ELEMENTS OF FELONIOUS HOMICIDE HAD BEEN PROVED SINCE MAINE HAD ABOLISHED THE DISTINCTION BETWEEN DIFFERENT TYPES OF HOMICIDE AND DESIGNATED MURDER AND MANSLAUGHTER AS PUNISHMENT CATEGORIES OF THE SINGLE CRIME OF FELONIOUS HOMICIDE. INSTEAD IT HELD THAT, IN SUBTANCE, MAINE DID RECOGNIZE DEGREES OF CULPABILITY BY IMPOSING SUBSTANTIALLY DIFFERENT PENALTIES BASED ON THE PUNISHMENT CATEGORIES AND WAS DENYING THE ACCUSED THE PROTECTION OF THE REASONABLE DOUBT STANDARD BY NOT REQUIRING THE PROSECUTION TO PROVE THE FACTS WHICH GIVE RISE TO THE DIFFERENCES IN DEGREE. THE APPLICATION OF THIS DECISION TO SOME OF THE COMMON AFFIRMATIVE DEFENSES, SUCH AS INSANITY, DURESS, NECESSITY, ENTRAPMENT, AND SELF-DEFENSE IS CONSIDERED. THE AUTHOR SUGGESTS THAT THE RATIONALE OF WILBUR WILL BE APPLIED TO THOSE DEFENSES WHICH CAN BE SAID TO NEGATE AN ELEMENT OF THE CRIME AND NOT TO THOSE WHICH EXCUSE THE COMMISSION OF A CRIME.