The Slave Trade and the Origins of International Human Rights Law

Book Cover for The Slave Trade and The Origins of International Human Rights Law

In the year 1800, slavery was normal. European countries used international law to authorize and justify the ownership of human beings. In the first decade of the nineteenth century, an estimated 609,000 slaves arrived in the New World. Within a relatively short time span, however, things began to change. In 1807, Britain became the first major seafaring country, followed shortly by the United States, to ban its subjects from participation in the slave trade. By the early 1840s, more than twenty nations—including all the Atlantic maritime powers—had signed international treaties committing to the abolition of the trade. By the late 1860s, only a few hundred slaves per year were illegally transported across the Atlantic. And by 1900, slavery itself had been outlawed in every country in the Western Hemisphere.

The abolition of the slave trade has received a great deal of attention from historians, but much less so from international lawyers. Yet the abolition of the transatlantic slave trade remains the most successful episode ever in the history of international human rights law. Slavery and the slave trade are among the few universally acknowledged crimes under international law. Though powerful countries today defend torture—another practice placed strictly off limits by international law—no nation today officially defends slavery. To be sure, modern forms of forced labor remain a significant human rights issue affecting millions of people, but the type of widespread, legalized chattel slavery that was commonplace in the nineteenth century has disappeared.

How did such a dramatic shift occur in disparate societies around the world in less than a century? Changes in the world economy in the nineteenth century certainly created the conditions that made the abolition of slavery more feasible. But the best historical evidence suggests that slavery did not die an accidental death of abandonment in the face of competition from industrial capitalism. Slavery was eradicated, intentionally, by people who had come to believe it was morally wrong. It was eradicated in part by military force, but also by coordinated international legal action—including, surprisingly, international courts.

Most people think of international courts as an innovation of the twentieth century, with the Nuremberg trials of the Nazi war criminals at the end of World War II being the first real effort to use international law to prosecute those accused of gross human rights abuses. But more than a century before Nuremberg, international courts in Sierra Leone, Cuba, Brazil, and other places around the Atlantic heard cases related to the slave trade, the original “crime against humanity.”

Though all but forgotten today, these slave trade courts were the first international human rights courts. Called the “Mixed Commissions” because they consisted of judges from different countries, the slave trade tribunals sat on a permanent, continuing basis, and they applied international law. The courts explicitly aimed to promote humanitarian objectives. Though the courts were extremely active for only a few years, over the treaties’ life span the courts heard more than six hundred cases and freed almost 80,000 slaves found aboard illegal slave trading vessels. During their peak years of operation, the courts heard cases that may have involved as many as one out of every five or six ships involved in the transatlantic slave trade. This book tells the story of these forgotten courts, a story that sheds important light on the origins of our contemporary system of international legal protection for human rights and also provides insight into issues faced by modern international tribunals like the International Criminal Court.

The history of the suppression of the transatlantic slave trade has implications for a number of contemporary debates about international law. Most legal scholars view international courts and international human rights law largely as post–World War II phenomena. But in fact, the nineteenth-century slavery abolition movement was the first successful international human rights campaign, and international treaties and courts were its central features. Indeed, even the phrase “crimes against humanity”—which came to modern fame based on its use at the Nuremberg trials—was used in the nineteenth century to describe the slave trade.

The abolition of the slave trade lies at a critical juncture in the history of international law and exemplifies a series of dichotomies and tensions that continue to play out even today, tensions between concepts of natural and universal law and law based solely on the positive enactments of a particular sovereign state; between religious and secular ideas of law and society; between European and non-European societies and cultures; between written treaties and unwritten customary law as the most important source of international legal norms; between national and territorial conceptions of jurisdiction and supranational or even universal jurisdiction. Thoroughly understanding how these tensions developed and were resolved (or left unresolved) in the context of the abolition of the transatlantic slave trade can help us better understand the jurisprudential foundations of modern international human rights law.

Moreover, this episode in the history of international law reveals a more complex interrelationship between state power, moral ideas, and domestic and international legal institutions than many contemporary theories of international law and relations acknowledge. Great Britain, the main instigator of the anti-
slavery treaties, no doubt would not have campaigned so strongly for abolition if it had been truly devastating to its economic and political interests. Yet substantial evidence shows that Britain’s abolition policy was motivated by genuine humanitarian concerns and that the policy inflicted significant economic costs on its empire. Of equal significance, Britain used international law as one important tool for persuading other countries to abandon a widespread and profitable practice. Britain was the nineteenth century’s greatest naval power, and its initial efforts to suppress the slave trade were military and unilateral, involving seizures of slave vessels by the British navy and condemnation of those ships in British courts. Over time, however, Britain found it could not rely on its military power alone but instead had to utilize that power in conjunction with cooperative legal action to achieve its goals. Over several decades, Britain convinced one country after another to ratify increasingly powerful treaties against the slave trade. At the same time, these international legal mechanisms would have been ineffective without Britain’s military and economic power. At critical moments, Britain was forced to deploy its “hard” powers, as well as its domestic laws and courts, to bring reluctant treaty partners back into the legal fold. In short, neither raw coercive power nor international law alone was enough to achieve the abolition of the slave trade. Both were necessary.

Each time and place in history is different, of course, and yet the use of international law to suppress the transatlantic slave trade in the nineteenth century is evocative of contemporary problems in international relations, including efforts to foster democracy and human rights both through the use of force and through legal institutions, including international and domestic courts. The antislavery movement’s use of international law and legal institutions as part of a broader social, political, and military strategy can help us better understand the potential role of international law today in bringing about improvements in human rights. In more theoretical terms, the history of the antislavery courts suggests a need for a thicker, more robust account of the relationship between power, ideas, and international law. In short, the forgotten bit of history recounted in this book should change the way we think about international courts and international human rights law—their origins, limits, and potential. SL

This excerpt is from Professor Martinez’s book The Slave Trade and the Origins of International Human Rights Law (Oxford University Press, forthcoming 2011).