I wrote my Master's Thesis on rape during the Civil War, so I will try to be brief on this topic. I could (and did) write hundreds of pages on this very topic. First off, the article is generally correct. Raping a black woman was not a crime against a person for much of the history of the United States. This is due to a variety of reasons which I'll try to summarize in the coming paragraphs. Secondly, I don't know why Casetext doesn't have older cases, perhaps they are growing still or don't list older cases, but I can assure there are thousands of known rape cases from the 19th century. I've read most of them!

One of the biggest challenge in answering this question succinctly is that the 19th century is a long period of time where US federal and state laws changed rapidly in different ways at different times in different parts of the country. The laws of Virginia and Maryland, which shared a border, could be drastically different regarding rape in the same year. You can also pick any state and it is likely they had evolving laws regarding rape as well as the century rolled on. The enforcement of these laws could vary from cities to rural areas, and as places became developed. Wildernesses of the early 19th century like Ohio and Kentucky quickly became settled law abiding areas within 20-30 years. Law enforcement also changed from part-time or volunteer constabularies and sheriffs to professional police forces by the end of the 19th century.

So lets just talk about the general evolution of rape law in the United States. First off, there was no federal law regarding rape for a long time. At the time of the founding it was assumed any of these criminal cases would be handled by the states, which they generally still are today. The federal government only concerned itself when a soldier committed rape. This means you have to look to individual territories and states to see what the law said regarding rape. They are pretty easy to find online if you poke around. By 1800 most states had gotten around to passing their own laws surrounding rape, and most aped Blackstone's (a famous English lawyer from the early 1700s) definition regarding rape. Whenever there wasn't a state law to cover an issue it was assumed that English Common Law was still generally the defacto law. Blackstone and English Common Law defined rape as a crime against a person which was “carnal knowledge of a woman, by force and against her will.” The punishment was, on paper, death, but often commuted to a lesser sentence. This was the same in the early United States.

When the states started passing their own laws regarding rape they became more and more specific than Blackstone. Separate punishments for white and non-white people were introduced. As a result the punishment for white people became less severe, while it was almost always death or some horrible humiliation like castration for non-white people. Generally people in the 19th century came to favor less severe punishments as time went on. For example, in 1801 Kentucky made rape a crime punishable by 10-21 years in prison instead of death as long as the victim was over 10 and the rapist was white. The penalty for non-white people who only attempted rape was death. Every slave state followed suit and made the crime rape punishable by death when committed by a non-white person. In 1837 in Virginia if you were white and helped a non-white person escape capture for rape you could be executed. Most non-slave states had generally softened punishments across the board and did not execute anyone for rape, but they still had harsher punishments for non-white offenders. By 1860 the punishment for rape, when committed by a white man, was usually about five years. In sentencing it was far lower.

But all of the above is really only for if the victim is white. What if the victim is black? Well if the victim was a slave and in a slave state, it simply wasn't considered a crime against a person. A master could rape his slaves as he pleased just like he could beat them nearly to death. If someone else raped his slaves it was a matter between the owner and the attacker. If there was damage done to the enslaved person during the commission of the crime they might seek restitution in court should the person be unwilling to pay up. Free black people had standing in court in theory in some states, but were often unable to bring cases to trial for a number of reasons. In most states north and south black people were usually deemed unsuitable to testify in court against a white person. They could only usually testify as supporting evidence, not as the only witness to a crime. They also faced a huge uphill battle dealing with juries that were all white and usually racist. This doesn't mean it never happened, just that it would be exceedingly rare. Even black people with iron clad cases likely faced community backlash or mobs should they seek justice.

We know all this through state laws and surviving court records, which are extensive. My work with Civil War court martial cases revealed several hundred cases. Some of soldiers raping women, some of garrisons in areas with martial law holding court in place of the civil courts. Law enforcement of the time was not so different than today. If you were the victim of a crime you went to the local law enforcement official who might be a guard, police officer, sheriff or what have you, and report the crime. The law enforcer would then investigate the crime, which involved questioning the person reporting the crime, and then usually arresting the possible attacker so they could go to trial. Law enforcement officers themselves did very little actual determination of motive or probable cause and so forth, that was left up to the courts. As a result they only actually arrested people when it was most obvious that they commissioned the crime. As a result not many people were likely arrested compared to the number of reports.

There were also likely few reports compared to today (of which there are still few reports). Victims of rape had to go through a pretty rough ordeal to prove rape happened, often including medical examinations and very difficult questioning days or hours after the crime may have taken place. There is no way around that unfortunately even today. But the 19th century society placed much of the burden on the accuser to establish the crime happened beyond a reasonable doubt, making convictions for rape very difficult. Rapists also had a veritable array of excuses that could get them off the hook or drastically reduce their sentencing. If they could sufficiently demean the woman's character in court (easily done with a few friends) then her testimony would be deemed incompetent or given less weight. Rounding up enough people to say that they knew she was a prostitute usually worked. They could also say she had lead them on and later changed her mind. When it came down to a man's word vs. a woman's courts tended to favor men. If the case is thrown out, and enough public testimony given that the woman is a known prostitute, she has just committed social suicide. Therefore, few women brought charges against men, and the few who did tended to be of lower class who didn't risk social outcasting.

I hope that helps some despite being rambly. I am approaching the post length limit so feel free to ask questions.