Girard looks at the French Revolutionary wars from the Caribbean end, where the doctrine that won battles in Europe ran up against the institutions the colonies were built on. Mass conscription was unthinkable where nine in ten inhabitants were enslaved and kept away from weapons, and free men of colour, who had served before, could hardly fight as citizen-soldiers for an order that refused them citizenship.

Emancipation, he argues, was worth more than tactics or naval support, since it could turn hundreds of thousands of enemies into allies at a stroke. The catch was that colonies without slaves might not be worth holding at all.

France's answer changed with its politics. Reluctant at first, it emancipated in 1794, and for the next four years the alliance with the formerly enslaved underwrote an aggressive strategy and plans for expeditions against British, Spanish and American territory. Bonaparte's restoration of slavery in 1802 lost the richest colonies despite massive white reinforcements.