Thomas Cobb says that there are not laws against raping an enslaved woman in the United States.
Thomas R. R. Cobb, "Of Personal Security.-Continued," An inquiry into the law of Negro slavery in the United States of America : To which is prefixed, an historical sketch of slavery (Savannah: W. Thorne Williams, 1858), 99-100
107. Another consequence of slavery is, that the violation of the person of a female slave, carries with it no other punishment than the damages which the master may recover for the trespass upon his property. Among the Romans there was also given the master, an action for the corruption of his slave, in which double damages were given. This, however, was founded also upon the idea of the injury to the property. Among the Lombards, if a master debauched his slave's wife, the slave and his wife were restored to their freedom. The laws of King Alfred provided a pecuniary compensation to the master for the ravishment of his slave. These laws are suggestive of defects in our own legislation.
It is a matter worthy the consideration of legislators, whether the offence of rape, committed upon a female slave, should not be indictable; and whether, when committed by the master, there should not be superadded the salve of the slave to some other master. The occurrence of such an offence is almost unheard of; and the known lasciviousness of the negro, renders the possibility of its occurrence very remote. Yet, for the honor of the statute-book, if it does occur, there should be an adequate punishment.