???

Are you seriously proposing that the loophole in the 13th was not placed there as a consolation to Southerners? I mean let's be frank here, the entire issue of slavery in the Northwest Ordinance was a compromise to Southerners. It wouldn't have passed otherwise. Fast forward to the end of the Civil War, and they chose the compromise in the Northwest Ordinance instead of the Sumner Amendment for the same reasons. Sumner's Amendment didn't even make it out of committee.

I don't see how anyone can say that slave states have not had an outsized influence on the slavery question as it is practiced in the US. They've had that influence, in my opinion, since our inception. It, (slavery), really was almost one of the original questions we had to answer at the founding of our Republic.

Yes: the "loophole" you're referring to is no such thing. It's language directly aimed at enabling felons (white, black, or otherwise) to be put to useful work. That's what everyone, everywhere, was doing at the time the law was drafted.

Imagine if Britain had been the one drafting the 13th amendment, at the same point in history. Removing this language would have meant giving up on the penal labor colony known as Australia. America was—not as famously—doing exactly the same thing.

???

Why would we have cared what Britain was doing?

They were our cold enemy during the Civil War. (At least, they were the cold enemy if you were on the Union side.)

What the rest of the world was doing was irrelevant to how the 13th was drafted. The war would be won. Slaves would be freed. The only questions we were considering was how to put that all down on paper. And for that question, the only thing that mattered was domestic politics.

Uh? I think you misread. I was pointing out that every major nation-state was running—and relying on the productive output of!—penal labor colonies in the 1800s. I brought up Britain as a well known example: everyone knows that Britain ran penal labor colonies. But the US was also running—and depending on—penal labor colonies.

The "loophole" is, to put it in modern terms, a concession to the American penal-labor-colony industry lobby. (Well, not really, since we didn't have private prisons back then. All the work being done by US penal labor colonies was directly to the productive benefit of the US government.)

Only it wasn't. The Northwest Ordinance was written the way it was specifically to appease slave states. It was calibrated so that slave states would outnumber free states by three even in the worst case. Everything from the slavery question, to the question of conditions under which territories would enter the Union, was settled in a fashion meant not to anger slave states. (Except, of course, for a few questions settled for what we, today, suspect were generous sums of money. But those were things like education. ie-where and how a university would be established.)

In fact, even a review of the Congressional Record, which I had the misfortune of having to do on these very two questions for a Capstone project back in undergrad, makes that very clear. It's obviously been a very long time, and the material involved was voluminous, but I can't recall offhand any mention of the penal labor industry. The debate was dominated by appeals to interests and even feelings of slave states.

Penal labor was very common in the 1860s. The UK, and its colonies, didn't ban penal labor until about 1950s. France didn't ban it until 1987. The statement was added to the Northwest Ordinance and the 13th Amendment, not as a sop to the Southerners to reintroduce slavery by backdoor means, but to ensure that someone couldn't look at the text and decide that the customary practice of penal labor would be considered outlawed.