The Slave Trade and the Origins of International Human Rights Law by Jenny S. Martinez (review)

According to Jenny S. Martinez, international efforts to end the slave trade formed the foundations of international human rights law. In support of this argument, Martinez surveys the history of nineteenth-century mixed commissions, courts authorized by binational treaties to adjudicate slave ship captures. The Slave Trade and the Origins of International Human Rights Law also seeks to uncover evidence of human rights discourse in the legal campaign against the slave trade, in particular references to slave trading as analogous to piracy. Martinez proposes that the incorporation of slave trade abolition in international human rights history results in a new narrative of international law, one that shifts the advent of human rights law back in time.

The book’s success in accomplishing these goals is uneven. Certainly, the turn to binational treaties and the establishment of mixed commissions to adjudicate slave ship captures are significant trends that deserve greater attention by historians. Martinez presents a measured account and valuable synthesis of the origins and operation of the mixed commissions. Her support for the human rights dimensions of the treaty regime is much less convincing.

The book’s overview of the ways in which the mixed courts functioned is based largely on documents in English collected by the British government and includes careful descriptions of the shortcomings of this system. (A global history of this nineteenth-century phenomenon based on non-English sources remains to be written.) The effectiveness of the courts varied: the commission at Sierra Leone had the highest rate of condemning captures and produced freedom for significant numbers of captives, whereas courts in Havana and Rio de Janeiro operated against local interests and resulted in the assignment of many freed captives as quasi-slaves. Significant holes in the international regime included long refusal by the United States to sign treaties recognizing the right of Britain to board and search U.S. ships in times of peace, persistent French non-participation, and the preservation by treaty of Portuguese slave ships’ rights to sail south of the equator.

The synthesis presented of these trends is very valuable. Yet Martinez is interested in it mainly as a preamble to her argument that the legal regime originated human rights law. To show this connection, Martinez must do more than assert that the international legal effort was on balance successful or demonstrate that it drew its inspiration from abolitionism as a humanitarian movement. She must show that the legal regime opposed to the slave trade relied on and promoted ideas about an internationally recognized prerogative to punish violators of universally held rights.

This argument requires some acrobatics. The mixed courts were set up to adjudicate ship captures. Neither the procedures nor the treaty language creating them made much mention of rights, and the courts did not depend on claims of universal jurisdiction. Procedures were modeled on those of prize courts, especially British vice-admiralty courts, where captives on board ships figured as cargo and their fate was determined by judgments about the nationality of ship owners, the origins and destinations of ships, the location of captures, and the courts’ jurisdiction. As Martinez acknowledges, one result was that the slaves rarely played an active role in the proceedings, either as legal actors or as bearers of rights.

More significantly, the mixed courts did not punish slave traders. Toward the end of their history, mixed commissions were empowered to hold slave ship crews and turn them over to national courts for punishment. But the mixed courts never charged, tried, or punished traders or crews on their own. To show that the mixed courts helped to lay the foundations for later efforts to establish international criminal jurisdiction over human rights abusers, Martinez must turn to evidence of attempts to equate slave trading with piracy as a crime against humanity. This exercise takes her away from the history of the mixed commissions. In a key...