The UN General Assembly on Thursday designated the transatlantic African slave trade as "the gravest crime against humanity," despite opposition from the United States and abstentions from several European countries including France, Germany and Britain.
In a move advocates hailed as a step towards healing and possible reparations, the resolution was adopted to applause by a vote of 123 in favour.
The United States, Israel and Argentina opposed the measure.
Ghana's President John Mahama, one of the African Union's most vocal supporters of slavery reparations, was at the UN headquarters in New York to support the vote.
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"Today, we come together in solemn solidarity to affirm truth and pursue a route to healing and reparative justice," said Mahama. "The adoption of this resolution serves as a safeguard against forgetting."
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Despite being non-binding, the resolution goes beyond simple acknowledgment and asks nations involved in the slave trade to engage in restorative justice.
It also highlights the legacy of slavery via "the persistence of racial discrimination and neo-colonialism" in today's society.
"The transatlantic slave trade was a crime against humanity that struck at the core of personhood, broke up families, and devastated communities," UN Secretary-General Antonio Guterres said.
"To justify the unjustifiable, slavery's proponents and beneficiaries constructed a racist ideology -- turning prejudice into a pseudoscience."
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During discussions over the resolution, the US ambassador Dan Negrea said the text was highly problematic.
"The US also does not recognise a legal right to reparations for historical wrongs that were not illegal under international law at the time they occurred," he added.
"The US also strongly objects to the resolution's attempt to rank crimes against humanity in any type of hierarchy."
Britain and EU countries advanced similar arguments while acknowledging the wrongs of slavery.
"The resolution risks pitting historical tragedies against each other that should not be compared, except at the expense of the memory of the victims," said French representative Sylvain Fournel.
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For African Union officials, the language of the resolution is central to its purpose.
Amma Adomaa Twum-Amoah, the AU's Commissioner for Health, Humanitarian Affairs and Development, said clearly naming these events removes any lingering ambiguity about their nature.
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"It is to say that what was done to Africans was not a tragic accident of history, but the result of deliberate policies whose legacies structure today's inequalities," she said. "Justice begins with calling things by their proper names."
Beyond recognition, the resolution encourages countries historically involved in the slave trade to engage in processes of restorative justice. Ghana's Foreign Minister, Samuel Okudzeto Ablakwa, has been explicit about what that could entail.
"The perpetrators of the transatlantic slave trade are known - the Europeans, the United States of America," he told reporters. "We expect all of them to formally apologise to Africa and to all people of African descent."
He pointed to the return of looted cultural artefacts as one possible step, alongside continued efforts to dismantle structural racism and, potentially, financial compensation for affected communities.
(With newswires)
