Wow, lots of replies are trying to downplay the existence ongoing human suffering.
A few things to consider:
- A disproportionate number of prisoners are African American, and that subset are mostly in prison for crimes that whites simply don't go to prison for (e.g., pot, or coke vs. crack).
- US prisoners aren't given nutritionally adequate food for free. They have to buy that at inflated prices from the prison. Once they blow through any savings, their only option (other than malnutrition) is to work for wages that would be illegally low outside of prison.
- As during the transatlantic trade, it is straightforward to buy your way out of forced prison labor.
- A growing fraction of prisoners consider the current system to be eugenics as well as slavery. The prisons take the majority of men while they are at prime child rearing age. It's well known that any that do manage to have kids will probably be forced into a situation where they can't adequately care for those children (dad goes to prison for driving while black or whatever), making the next generation easy targets for the same scheme. (This is coming from current prisoners, not me.)
The other pushback against my comment boils down to "it's legal, so we don't use that word". Similar arguments were made in defense of the transatlantic trade. For instance, black Africans were generally the ones selling slaves, and often used real or imagined criminal records as an excuse. Any objective comparison of the two systems would find that the transatlantic slave trade was roughly as immoral California's three strike law is in practice. You could argue the slave trade was worse because the kids were automatically slaves. In the current system, they're only probably going to prison, but the prisons also aren't paying to raise them.
I suggest reading Things Fall Apart if you're unfamiliar with the African side of the slave trade.