Slavery is a crime against humanity because it claims ownership of a person. The Rome Statute defines enslavement as “the exercise of any or all of the powers attaching to the right of ownership over a person”, and it treats that exercise as a crime against humanity when committed as part of a widespread or systematic attack against a civilian population. The wrong is not the extraction of labour. The wrong is the reduction of a person to a thing — a thing that can be owned, transferred, and used.
Debt is not that. Debt is a claim on a defined performance: a sum of money, a schedule of repayment, an obligation with a term. A creditor does not own the debtor. The creditor owns a right to be paid. The debtor remains a person, with rights, with an exit, with a life that is not the creditor’s property.
That is why the phrase “debt is voluntary slavery” is a metaphor and not a definition. It captures the experience of being trapped by an obligation. It does not capture the structure of slavery, because slavery is a status and debt is a contract.
But the metaphor becomes literal when the contract is allowed to become a status.
When debt becomes slavery
International law already names the threshold.
Debt bondage is defined in the 1956 Supplementary Convention on the Abolition of Slavery as “the status or condition arising from a pledge by a debtor of his personal services or of those of a person under his control as security for a debt, if the value of those services as reasonably assessed is not applied towards the liquidation of the debt or the length and nature of those services are not respectively limited and defined”.
Read that definition carefully. It contains the two things that turn a contract into a status.
The value is not applied to the debt. The debtor works, but the work does not reduce the obligation. The debt is a treadmill. The labour is not payment; it is the condition of being allowed to continue owing.
The length and nature of the services are not limited and defined. The debtor does not know when it ends. The obligation is open-ended. The creditor can demand more, for longer, in forms that were never specified.
When both conditions are present, the debtor is not servicing a contract. The debtor is servicing a status. The person has become the security. That is the point at which debt stops being a claim on a performance and becomes a claim on a person.
The ILO’s forced labour definition points at the same boundary from the other direction. Forced labour is “all work or service which is exacted from any person under the menace of any penalty and for which the said person has not offered himself voluntarily”. The ILO’s indicators of forced labour include debt bondage, retention of identity documents, and restriction of movement. The presence of those indicators is what turns a debt into a coercion.
That is slavery-like, and it is prohibited.
What makes debt good
Debt is not good because it is voluntary. Plenty of bad things are voluntary. Debt is good when it has four features, and each of them preserves the person behind the contract.
First, it is genuinely volunteered. Not “voluntary” in the thin sense that no one held a gun to the debtor’s head. Voluntary in the meaningful sense that the debtor had a real alternative, understood the terms, and could refuse without losing her home, her safety, or her ability to live. Coerced debt — debt incurred under trafficking, deception, or dependency — is not a contract. It is an instrument of control.
Second, the terms are fair. Fair means transparent, intelligible, and bounded. The interest rate is disclosed. The total cost is disclosed. There are limits on usury, because a rate that can never be repaid is not a price; it is a capture mechanism. The terms are clear enough that the debtor can see the exit, and the exit is real. The consumer credit framework in the United States, for example, prohibits creditors from discriminating on protected grounds and requires that the variables used in a credit model have “documented, legitimate business justifications” where they produce a disproportionate effect. Usury laws and state debt collection practices laws impose further limits on what a creditor can charge and how it can collect.
Third, credit scoring is fair and explainable. A credit system that decides who gets access to capital on the basis of arbitrary, hidden, or discriminatory criteria is not a market. It is a gate. Fair credit scoring requires accuracy, transparency, and a genuine explanation of why a decision was made. The EU’s General Data Protection Regulation requires that a data subject be able to obtain “a clear and comprehensible explanation of the assessment of creditworthiness”. The Court of Justice of the European Union has held that the explanation must be “concise, transparent, intelligible, and easily accessible”, and that merely providing information is insufficient if people cannot comprehend it. The point is not bureaucracy. The point is that a person cannot contest a decision they cannot understand.
Fourth, collection is limited. A creditor may pursue a debt. A creditor may not become a power over the debtor’s life. Collection must be discreet, must not use threats or unreasonable pressure, and must not make the debtor’s situation worse in order to extract payment. The US Fair Debt Collection Practices Act and its Regulation F provide “guidelines and limitations concerning the conduct of certain creditors and third-party debt collectors in connection with the collection of consumer debts”. The debtor remains a person after default. The obligation does not purchase the person.
When all four features are present, debt is a contract between free people with an exit. It is not good because it is painful. It is good because it is bounded. The debtor can see the end, can plan for it, and can remain a person while servicing it.
The difference in one sentence
Slavery is a claim on the person. Debt is a claim on the performance.
A claim on the performance can be good. It can build a house, start a business, pay for an education, bridge a bad year. It can be fair, transparent, scored, and collected within limits. It can leave the debtor standing.
A claim on the person is a crime against humanity. It does not end. It does not define its terms. It does not apply the value of the labour to the debt. It turns the debtor into the security, and the security into a status.
Debt is voluntary slavery only when it stops being voluntary, stops being fair, stops being bounded, and stops being collection. Until then, it is a contract. After that, it is a ledger with a person inside it.
The task is not to abolish the ledger. The task is to keep the person out of it.
References
Court of Justice of the European Union. (2025, February 27). Dun & Bradstreet Austria, Case C-203/22.
Fair Debt Collection Practices Act, 15 U.S.C. § 1692 et seq. (US).
International Labour Organization. (2007). Trafficking and labour exploitation of West African immigrants in the Netherlands (Working Paper 55).
Regulation (EU) 2016/679 (General Data Protection Regulation), Article 15(1)(h).
Rome Statute of the International Criminal Court. (1998). Article 7(1)(c), Article 7(2)(c).
Supplementary Convention on the Abolition of Slavery, the Slave Trade, and Institutions and Practices Similar to Slavery. (1956). Article 1(a).
United Nations. (2000). Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children (Palermo Protocol), Article 3.