Outlook Explainer: Why Did The United Nations Call Slavery The Gravest Crime?

When the United Nations General Assembly resolution declared the transatlantic slave trade “the gravest crime against humanity,” it did more than restate a moral truth. The declaration changed the vocabulary of accountability over the slave trade.   Up until now the countries responsible for the slave trade—the US, Europe and Britain---largely acknowledged the moral truth about it, but they don’t want to take material responsibility of it, and are against the idea of “reparatory justice.” That is the reason why three countries— the United States, Israel and Argentina—voted against and Britain and member states of the European Union were absent during the voting of the declaration.  

The UN resolution goes beyond recognition, urging nations involved in the slave trade to engage in reparatory justice, including formal apologies, compensation and measures to address systemic discrimination. It also calls for the “prompt and unhindered restitution” of cultural items such as artworks, monuments and archives to their countries of origin. 

For centuries, the transatlantic slave trade underpinned the making of the modern world. Between the 1500s and the 1800s, European empires forcibly transported millions of Africans across the Atlantic, feeding plantation economies in the Americas. Human beings were reduced to property—insured, traded, and inherited. The violence was  structural part of it. Death, displacement, and dehumanisation were built into the system.

The United States and the United Kingdom were central actors in the slave trade. Enslaved labour powered the American economy well into the 19th century, while British ships dominated the transatlantic trade for decades. The profits generated during this period helped build national wealth that persists across generations. 

The UN resolution talks about reparations because the wealth extracted from enslaved labour did not vanish with abolition. It was reinvested into industries, infrastructure, and financial systems that continue to shape global inequalities. The afterlives of slavery—racial hierarchies, economic disparities, and institutional discrimination—remain embedded in contemporary societies. 

Reparations, in whatever form—financial compensation, debt relief, institutional investment, or formal apology—would require the US, Britain and Europe to move from symbolic recognition to material commitment. That has economic costs which they do not want to take. 

For the African states which were pushing for the motion, the resolution is not just about the past. It is about the present. Their argument is straightforward: if slavery was foundational to the global economic order, then its consequences are not historical artefacts but ongoing conditions. Underdevelopment, debt burdens, and racial inequality are not disconnected phenomena; they are part of a long arc that begins with extraction and exploitation. It is precisely this framing of the resolution that made the countries responsible for the slave trade oppose the resolution.

The language of the resolution strengthens the intellectual and political case for reparations.  While UN General Assembly resolutions are not legally binding, they help shape normative frameworks—what is considered legitimate, actionable, and urgent. By intensifying the moral classification of slavery, the resolution inevitably sharpens demands for redress.

In 2014 African-American journalist Ta-Nehisi Coates shot to fame when he wrote an essay titled “The Case for Reparations” which advocated reparatory justice for the brutalities of slavery and Jim Crow years.

In 2019 he addressed a Congressional hearing on reparations where he said that the “matter of reparations is one of making amends.”

“Yesterday, when asked about reparations, Senate Majority Leader Mitch McConnell offered a familiar reply: America should not be held liable for something that happened 150 years ago, since none of us currently alive are responsible. This rebuttal proffers a strange theory of governance – that American accounts are somehow bound by the lifetime of its generations. But well into this century, the United States was still paying out pensions to the heirs of civil war soldiers. We honor treaties that date back some 200 years, despite no one being alive who signed those treaties,” he said.