In September 2015, a municipal judge in a small Georgia town was secretly recorded threatening defendants with immediate jail if they could not pay their traffic tickets on the spot. This episode asks how that is possible in a country that supposedly abolished debtors’ prisons in the 1830s. The answer begins in medieval Europe, where debtors were locked in single-cell dungeons and charged for their own room and board, and runs through industrial England, where 10,000 people a year were jailed for debt and wealthy inmates could buy the liberty of the rules and live outside the walls.

America imported the system whole, and it swallowed signers of the Declaration of Independence before the crash that followed the War of 1812 filled the jails with ordinary farmers and tradesmen and turned public opinion. Federal law ended imprisonment for debt in 1833. Yet a 2010 Brennan Center for Justice study found jurisdictions in all 15 states it examined still arresting people over debt, through a loophole that punishes not poverty itself but willful nonpayment and contempt of court.

• Charles Dickens saw his father sent to the Marshalsea as a child, an experience that inspired Little Dorrit and a lifetime of reform advocacy.
• Robert Morris, financier of the Revolution, spent 1798 to 1801 in Philadelphia’s Prune Street debtors’ prison after land speculation collapsed. Supreme Court justice James Wilson was jailed for debt as well.
• Supreme Court rulings including Bearden v. Georgia bar jailing people solely for being too poor to pay, which leaves the meaning of willful to each judge’s discretion.
• The Brennan Center identified four traps: debt as a probation condition, civil contempt, programs that let defendants choose jail to pay down fines, and arrests for missed hearings.
• Canada converts unpaid criminal fines into jail days using the provincial minimum wage, while expatriates in Dubai flee the country rather than face prison over a defaulted loan.