The double liability problem becomes acute at the individual level when you consider that many British people have heritage from multiple nations, including nations that participated in the slave trade to different degrees. A British person with one English parent and one Portuguese parent, for example, has ancestry from the two largest slave-trading nations in the Atlantic trade. Under the reparations logic, they carry liability from both lines of descent.
There is no mechanism for resolving this. Which country’s levy applies? Both? A weighted average based on how many enslaved people each nation transported? Does the Portuguese liability offset some of the British liability because Portugal started the trade? These questions sound absurd because they are absurd, but they follow directly from the logic of national liability for historical slave trading applied to individuals with dual national heritage.
More broadly, British people with heritage from any slave-trading nation, France, the Netherlands, Denmark, Spain, as well as Portugal and Britain, face the same arbitrage problem. And British people whose heritage includes African nations that supplied enslaved people to the trade face a further complication: they carry both the claimed right to receive reparations and some portion of the claimed liability to pay them.
The impossibility of resolving these questions at the individual level is not a peripheral problem. It is a symptom of the fundamental incoherence of applying national liability for historical events to individuals in a diverse modern society.
