The problem in rape cases is not this criterion [mens rea] as such but the manner in which it has been interpreted, in particular in the morgan case in britain and in the mayberry case in the state of california. these cases created a totally new defense to the crime of rape, the defense of a mistake-of-fact as to consent.47 it was ruled in morgan that a mans belief in a womans consent did not have to be a reasonable belief, and in mayberry that a jury must specifically reject a defense of reasonable but mistaken belief in consent.