President Lincoln when talking about the struggle of his countries Civil War, and his desire to see it through its end said, “Yet, if God wills that it continue until all the wealth piled by the bondsman's two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash shall be paid by another drawn with the sword..” Lincoln is proposing that the destruction of the civil war could be seen in part as punishment (Justice) for the misery and death allowed to perpetuate by the nation prior.
Logically, if that were the case, slavery world wide would need to also have been ended in a destructive struggle. I propose that the Napoleonic wars were that struggle, and that the most decisive blow against slavery was inadvertently dealt because of it.
The greatest blow ever dealt slavery was when the British Parliament outlawed the slave trade – not just for themselves but for every nation that sailed upon the deep. This simply couldn’t have happened without the Napoleonic wars.
Without the backdrop of war a measure that called for regulating all shipping on the seas not just British ships – would have been considered absurd. Such a course would surely lead to war – as in fact it did in 1812 with the Americans, upset that their commercial shipping was routinely boarded by the British. While it was true that many British citizens were sympathetic to the plight of slaves, it is doubtful they would have risked a major war to hinder the practice. In the middle of wartime however, the risk was minimal as Britain already was at war---and shipping everywhere was interdicted.
Since this ban was universal, it severely weakened the whole institution. First, in the future the mass expansion of slavery would be impracticable. Secondly, the practice of working slaves to death and then replacing them cheaply with ones fresh from Africa was no longer viable. If slavery was to survive it would have to be by treating the slaves well enough that they could replace their own numbers or even increase their populations.
The effect of this was to reduce the profitability of slavery drastically. In the long term, the economic system of slavery could not grow, (economically speaking), as quickly as the competing free labor system. With its economic power fading, slave owning societies lost power and eventually were defeated by anti-slavery factions both as internal politics and international politics. A good example of this is the divergence of the economic fortunes of the South and the North after the ban and its eventual conclusion in the American Civil War. Both economies grew, but the North simply outpaced the South.
In less than a century after the slave trade was banned, slavery was almost non-existent all over the globe. It is most fortuitous for humanity that cheap supplies of slaves were abolished just at the moment that the Industrial Revolution began in earnest. Certainly the inhumanities of that revolution took a mighty struggle to correct – and that was in a free labor markets system! I do not wish to imagine the horror that could conceivably have resulted.
Blood drawn --- 750,000 American CW, 4-5 million in the Napoleonic Wars
A lot of treasure lost in both wars.
Slaves brought across the atlantic, to North and S.America approx 15 million.