Debtors Prison came back to America a long time ago when they started jailing men for failing to pay court-ordered child support.
In answer to one question posted: You're not supposed to be able to pay your debt locked up in jail. That's not the point. If a relative or someone pays the debt to free you that's nice. The real point is to show the subjects who's the boss and who's the serf. America is becoming less free every day.