In rape cases involving physical violence or express threats of physical harm, proof of the actus reus obviously does establish mens rea with respect to force as well as nonconsent. A defendant who beat or threatened to kill his victim could hardly raise a plausible argument that he did not know he was using force. But, in other circumstances, the defendant's mens rea vis-a-vis force may be less clear, and it may therefore make a difference whether a rape conviction requires proof that the defendant purposely intended to use force, or whether it is enough that he knew he was exercising force, that the woman thought he was using force, or that a reasonable person viewing the situation would have thought so. Given the traditional criminal law assumption that a mens rea requirement attaches to every material element of a crime, it seems odd that so little attention has been paid to the question of what mens rea, if any, attaches to the force element.
Admittedly, a handful of courts have paid lip service to this issue, and their opinions are described below in Part II. But the overwhelming majority of court decisions and commentaries discussing mens rea and rape have focused exclusively on the defendant's beliefs and mistakes about the victim's consent. As explained in Part III, this almost universal disregard of mens rea issues as applied to the element of force confirms the redundancy of the force requirement, once absence of consent and its accompanying mens rea have been established.
Kit Kinports, Rape and Force: The Forgotten Mens Rea, 4 Buff. Crim. L. Rev. 755 (2001).