After abolishing the slave trade in its empire in 1807 and winning a decisive victory in the Napoleonic Wars in 1815, Britain attempted to create a network of “mixed courts” with several other European nations and the United States in the early to mid-nineteenth century. Comprised of judges from each of the cooperating nations, these courts were designed to adjudicate allegations of illegal slave trading and condemn slaving ships. Although the United States had abolished its own international slave trade in 1808, it initially declined overtures to participate in mixed courts as part of its treaty arrangements with Britain.
During the U.S. Civil War, however, the Lincoln administration was eager to avoid the prospect of Britain joining the Confederate cause in the interests of reopening the transatlantic cotton trade. As part of the agreements that ultimately preserved peace with Britain, the administration entered into (and the U.S. Senate unanimously ratified) the Lyons-Seward Treaty in 1862 (12 Stat. 1225). The treaty’s primary purpose was to suppress the slave trade in British and American ports and waters.
The treaty created three mixed courts to be staffed by an equal number of British and American judges for the purposes of adjudicating cases arising under its provisions. The courts were to be held in New York, Sierra Leone, and the Cape of Good Hope (the latter two sites were then under the control of the British Empire). There was to be no appeal from the courts. In cases in which the British and American judge disagreed on a significant issue, the regulations annexed to the treaty set up an unusual tiebreaking system, whereby both nations appointed an “adjudicator,” one of whom was selected by the drawing of lots. The selected adjudicator then consulted with the two judges and voted on the case, with the final sentence or decision reflecting the majority position on each issue.
The illegal transport of slaves from Africa to America dwindled in the years following the treaty’s proclamation. The eventual abolition of slavery in the United States made future large-scale illegal importation of slaves highly unlikely. As a result, although the judges remained in office and were paid a salary until the courts were abolished in 1870, they never heard a case.
Eugene Kontorovich, “The Constitutionality of International Courts: The Forgotten Precedent of Slave Trade Tribunals,” Northwestern University Faculty Working Papers, Paper 178 (2010).