Most countries around the world have confined debtors' prisons the annals of history. Indigent debtors can, however, still be locked away in the United Arab Emirates, Greece and, to (what should be) our shame, the United States.

The US did away with designated facilities for jailing debtors in the 19th century. But the system of imprisoning the poor for their failure to pay legal fees persists, feeding the glutted incarceration system.

The 14th Amendment holds that it is unconstitutional to imprison individuals for debts they can't pay (there is a caveat for willful debt refusal) but, as the ACLU noted in 2012, the incarceration of debtors has become "a growing problem nationwide." The problem lies in the legal small print — judges are left to decide what might constitute a "willful" failure to pay a debt, and across the country individuals too poor to pay fines are being punished as "willful" defaulters.

As NPR reported in May: "Some judges will tell an offender to give up their phone service, or quit smoking cigarettes — and use the money instead to pay court debt." It is unabashed discrimination against America's poor.

In 15 states, including Minnesota, Arkansas, Washington, and Arizona, we have seen a significant uptick in arrest warrants for debtors, relating to debts originally owed to private firms. However, there are no national statistics about the proliferation of debtor imprisonments. Yet a spread of anecdotes, followed by civil liberties groups like the Southern Poverty Law Center and the ACLU, point to a trend now firmly established in US so-called justice.

The pattern that leads an indigent debtor is as follows: It starts with basic debt, including credit card, medical, unpaid rent, and a host of unpaid fees to private firms. Debts become fines when collectors take debtors to civil court and from there, court fees are accrued. These court fees, if unpaid, can become grounds for incarceration.

The financial crisis prompted a rise in debtor incarcerations, not only by virtue of the widespread financial ruin entailed by the mortgage crisis, but also through the rise of vulturous collections firms.

That recent NPR investigation found just how common this is: "In Benton County, Wash., for example, jail records obtained by NPR and sampled over a four-month period in 2013 show that on a typical day, a quarter of the people who were in jail for misdemeanor offenses were there because they had failed to pay their court fines and fees."

Clearly, debtors prisons are a vile trap. The most likely individuals to face claims over unpaid debts are America's poorest, therefore the least likely to be able to pay legal fines on their existing debt.

The financial crisis prompted a rise in debtor incarcerations, not only by virtue of the widespread financial ruin entailed by the mortgage crisis, but also through the rise of vulturous collections firms. As Yves Smith noted in 2010: "What is new is the rise of well-funded, aggressive and centralized collection firms, in many cases run by attorneys, that buy up unpaid debt and use the courts to collect. Three debt buyers — Unifund CCR Partners, Portfolio Recovery Associates Inc. and Debt Equities LLC — accounted for 15 percent of all debt-related arrest warrants issued in Minnesota since 2005, court data shows."

A pernicious moralism permeates the rebirth of debtors' prisons, which is both punitive and cautionary. It accords a moral value, worthy of criminal punishment, to the meeting of financial obligations. But we have seen too much, we know too well that private debts are economy-crippling bloodsucking mites.

As anthropologist David Graeber wrote in his hit book Debt: "The struggle between rich and poor has largely taken the form of conflicts between creditors and debtors — of arguments about the rights and wrongs of interest payments, debt peonage, amnesty, repossession, restitution, the sequestering of sheep, the seizing of vineyards, and the selling of debtors’ children into slavery."

Debtors prisons also function as a grim deterrent against tactical default. They are a state weapon fighting the rise of debt resistance at a time when debt refusal seems not only a reasonable choice, but an ethical one.

There is, Graeber also points out, an ahistorical reading of the debt relationship with our current punishment of the debtor. Namely, our contemporary treatment forgets that the lender takes a certain risk in making a loan, that risk is inscribed in the lender-debtor relation. But now the burden of unpaid debts falls wholly and aggressively on the indigent debtor.

Debtors prisons — and the entire credit economy today — endorse this modern view of debt in which only the debtor, not the lender, can be faulted for the failure of payment. It is yet another example that shows exactly what and whom is served by the justice system. In criminalizing burdened borrowers, the justice system proves itself a brutish servant of capital.

Follow Natasha Lennard on Twitter: @natashalennard