I wasn't referring to prison labor although that is a valid discussion too. It's ironic that the "land of the free" only leads in incarcerated citizens, obesity, and diabetes per capita.

I also don't have a reference on hand. I listened to an NPR radio segment that blew my mind. There's a bunch of information from reputable sources but finding a specific number can be tricky. First of all, it's estimated because it's obviously unknown. Also, defining the "bounds" of slavery inherently changes the count. There is a fairly recent citation that states there are 400,000 enslaved people in the United States on any given day.

https://www.state.gov/what-is-modern-slavery/

https://en.wikipedia.org/wiki/Human_trafficking_in_the_Unite...

https://www.cbp.gov/border-security/human-trafficking

https://www.theguardian.com/world/2018/jul/19/us-modern-slav...

> The constitution doesn't consider that slavery but the rest of the world certainly can.

It does actually.

Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.

Indeed. Thirteenth amendment, section 1.

Most places skirt that by paying the inmates for the work. However, the pay determined was decided in 1896 at 27p/day. That's 27 cents. A day. It might have changed over the years but that's what it was in Virginia when my step-father was a judge.

https://www.prisonpolicy.org/blog/2017/04/10/wages/

> The constitution doesn't consider that slavery but the rest of the world certainly can.

Section 1 of the 13th Amendment explicitly refers to this as slavery:

“Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.”

https://en.m.wikipedia.org/wiki/Thirteenth_Amendment_to_the_...