Freedom International: The United States and the Suppression of the Slave Trade, 1860-1867

by Christopher Dunn


The end of the Atlantic slave trade was one of the most impressive acts of international cooperation of the nineteenth century. In just about 50 years, the 300-year-old business of carrying African slaves across the Atlantic from West Africa to the Americas was eradicated. This effort was almost entirely carried out by Great Britain, which used its naval power to enforce the international treaties and laws that banned the slave trade in the international legal sphere.[1] But efforts to end the international slave trade would not be possible without the cooperation of the United States. This cooperation came late, but starting with the election of 1860, the new Lincoln Administration adopted a dynamic and multi-pronged effort to end the slave trade that ultimately led to the signing of the Lyons-Seward treaty of 1862. While the same administration was bringing down the domestic institution of slavery, it was involved in the suppression of the slave trade around the Atlantic world.

Background: The U.S. and the Antebellum Slave Trade

From the beginning of the nineteenth century, the United States federal government was involved in legislation aimed at ending the international slave trade. In March of 1807, President Jefferson signed a law outlawing the international slave trade to the U.S. The law made it illegal to import slaves into the United States as well as for American citizens to be involved in any way with the slave trade to the U.S.[2] In his 1806 State of the Union speech, Jefferson, himself a slave owner, alluded to the upcoming law, arguing for the need “to withdraw the citizens of the United States from all further participation in those violations of human rights which have been so long continued on the unoffending inhabitants of Africa, and which the morality, the reputation, and the best of our country have long been eager to proscribe.”[3]

In 1820, the U.S. took this prohibition a step further. The previous year, a law had passed that outlawed piracy, and in May of 1820, that law was amended so that the slave trade was included under piracy. Under the new law, U.S. citizens who worked on ships engaged in the slave trade or any person working on a ship owned by U.S. citizens involved in the trade could be tried as a pirate, punishable by death.[4] This law not only raised the potential penalty for involvement in the slave trade from the 1807 law; it made it illegal not just to import slaves into the United States, but to engage in any slave trading. American ships bringing slaves from West Africa to Cuba or South America could then be prosecuted under American law.

Given the scope of the slave trade and the difficulties of enforcing the laws, effective enforcement would have to be an international effort. Great Britain, which had abolished slavery in its empire in 1833, led the way in this effort. In 1842, the U.S. and Great Britain signed the Webster-Ashburton Treaty. The treaty covered disputed territory in North America and “The Final Suppression of the African Slave-Trade.” Article VIII of the treaty outlined a plan in which each of the two countries would “prepare, equip, and maintain in service, on the coast of Africa, a sufficient and adequate squadron…to enforce, separately and respectively, the laws, rights, and obligations of each of the two countries, for the suppression of the slave trade.”[5] 

Even with these provisions, the slave trade flourished in the antebellum period, with the U.S. often turning a blind eye to their citizens who engaged in the trade. During this period, American ships would be outfitted in New York and bring human cargo across the Atlantic from West Africa to either Cuba or Brazil.[6] They were able to do so because the United States refused to grant the Royal Navy right of search, which would allow the British to inspect ships flying the American flag that were suspected of trafficking slaves. While the British entered into agreements that allowed such a right with other European powers, they never entered one with the United States, and so slavers could avoid the British ships by flying the American flag.[7]

A Change in American Policy, 1860-1861

The Election of 1860

The Republican Party represented the biggest threat to the power of slavery both in the U.S. and abroad, and the election of Abraham Lincoln in 1860 marked the beginning of America’s real involvement in ending the international slave trade. Before they took power, the Republicans made clear that they were intent on stopping slavery. The party’s 1860 platform declared “That the normal condition of all the territory of the United States is that of freedom…”[8] This was more than just a rhetorical claim. It was a constitutional one. This was the theory of “Freedom National, Slavery Sectional,” which anti-slavery politicians and activists used to reason that slavery was not the natural state of anywhere in the United States. Instead, the U.S. Constitution made the national policy one of freedom, with slavery existing as an abnormality in some specific areas of the country.[9]

The platform did not only declare the party’s opposition to the spread of slavery in the United States. Indeed, Republicans made very clear their intention to use the force of the U.S. government to combat the slave trade. This time taking a more rhetorical route, the Republicans called the slave trade “a crime against humanity and a burning shame to our country and age” and declared the need “to take prompt and efficient measures for the total and final suppression of that execrable traffic.”[10]

The Early Lincoln Administration

The newly elected President Lincoln took a much more conciliatory approach to the issue in his first public address. Perhaps in an attempt not to upset the southern states and make the ongoing secession crisis worse, Lincoln said that the international slave trade was “imperfectly suppressed,” but that this problem could “not be perfectly cured.” Contrasting the law outlawing the slave trade with the Fugitive-Slave Act, Lincoln wrote that neither was perfect in its enforcement, but this was to be expected in a country where so many people disagreed on the issue of slavery. The status quo—where not all runaway slaves were returned to their owners and some slave trading still existed—would be better, he said, than the prospect of secession.[11]

But Lincoln’s words were not enough to keep the South in the Union, and he quickly showed through his actions that he was ready to take on the slave trade. On May 2nd, 1861, less than two months after his inaugural address, Lincoln wrote a memo to Caleb Blood Smith, his Secretary of the Interior, charging the Department of the Interior with carrying out the U.S.’s enforcement of laws against the slave trade. Smith took this charge seriously, writing that “The subject was immediately taken in hand, under a deep sense of our obligation as a nation, to put an end, if possible, to this odious traffic…” Smith gathered U.S. Marshalls in New York to show what a fully-equipped slave ship would look like and sent them to Northern ports along the Eastern Seaboard to inspect ships and detain those that would be used for the slave trade. By all accounts, this effort was successful; within seven months, five ships had been caught and their owners tried.[12]

Nathaniel Gordon Case

Of all of these cases, none gained as much public attention as that of Nathaniel Gordon, the American captain of the slave ship Erie. Gordon’s ship was captured in 1860 off the coast of West Africa with 867 Africans on board. There were 211 men, 130 women, 366 boys, and 160 girls, all of whom were eventually sent to Liberia.[13] James I. Roosevelt, the U.S. Attorney for the Southern District of New York and a Democrat, initially refused to bring the case to trial, but when E. Delafield Smith took over the position, he quickly brought charges against Gordon, and, in November of 1861, Gordon was found guilty and sentenced to death.[14] Smith was a Republican who was dedicated to the issue of ending the slave trade in New York, and he was clear that his prosecuting Gordon was part of this plan. In a letter to Montgomery Blair, the Postmaster General, Smith wrote that “Three things are required to end the slave trade at this port: First, To stop the fitting out; Secondly, To restrain American officers and seamen from serving on slave ships; and Thirdly, To extirpate “Straw Bail” for vessels seized for the offence and then bonded or bailed and discharged.” The second, he suggested, was complete with the execution of Gordon.[15]

Gordon’s case did not end with his conviction. As no one had ever been convicted under the 1820 law before him, it was unclear if the government would really carry out its sentence. The federal government, however, stood its ground, showing how serious they were about making an example of Gordon. After several thousand citizens of New York petitioned to have Gordon’s sentence commuted to life in prison, Lincoln only granted a two-week stay on the execution until February 21.[16] Not even a petition from Gordon’s twenty-two-year-old wife and aging mother could persuade Lincoln to change the sentence.[17] Gordon was hanged on February 21, 1862, the only American to ever face the death penalty for their role in the slave trade.[18]

For opponents of the slave trade, the execution served as a well-received sign that the United States was finally ready to enforce its laws. The anti-slavery New York Times eloquently expressed the sentiment, writing that:

 “…we cannot but rejoice that the Slave-trade has received so heavy a blow. Our city has been disgraced by it long enough. Our whole country has shared in that disgrace. We rejoice in the belief that the prospects are brighter for the future, and the sternness with which the law has been carried out in this instance will be effectual for the destruction of so enormous a crime within the borders of not only this City, but of the whole land.”[19]

The Lyons-Seward Treaty

The Blockade and the Africa Squadron

As Gordon was being executed for his participation in the slave trade, events in the U.S. were making it harder for the Navy to patrol West Africa. Part of the Union effort in the Civil War was a Naval blockade of the American South, for which the Navy would need all the ships it could get. By December of 1861, the Navy had brought over seven ships from the West African coast: the Constellation, the Portsmouth, the Mohican—which had originally captured Gordon a little over a year earlier—,the Mystic, the Sumter, the San Jacinto, and the Relief. Only one ship, the Saratoga, an 18-gun sloop, was to remain off the coast of Africa.[20]

This reduction in the Africa Squadron left the United States well below the requirement laid out in the Webster-Ashburton Treaty. Because the U.S. never had agreed to a treaty of right of search with the British, they were virtually incapable of patrolling West Africa for slavers. By the early Civil War, such a treaty looked less and less likely as tensions between the U.S. and Great Britain increased. In November of 1861, the U.S.S. San Jacinto stopped the Trent, a British mail ship, off the coast of Cuba. The ship had on board two Confederate diplomats who were going to Britain with the intention of gaining British recognition of their cause, and the Captain of the San Jacinto forcibly boarded the Trent and arrested the Confederates. This started off a diplomatic incident which nearly brought the two nations to war.[21]

By early 1862, however, tensions between the United States and Great Britain had decreased, and the possibility of a joint effort to combat the slave trade became more likely. In a February 28 letter from John Russell, the British Foreign Minister, to Richard Lyons, the British Ambassador to the United States, Russell suggested as such. He summarized the problem, writing that “The result is that American Cruizers [sic] are taken away from the African coast on the ground of the Civil War, while British Cruizers are kept away from the Cuban coast in deference to American jealousy with respect to the United States flag.” Russell suggested two options to solve this: that the U.S. increase the size of its Africa squadron, or that the country finally grant Britain the right of search. Knowing that the Civil War made it all but impossible to carry out the former, Russell included in his letter a draft treaty, which granted each navy the right of search of ships carrying the other’s flag, for Lyons to share with the Americans.[22] He trusted that such an effort would be successful, since “Her Majesty’s Government are fully convinced of the sincerity of the United States Government in their professions of a desire to suppress the Slave Trade. This desire is in conformity with the well known sentiment of the President and the principal Members of his Administration.”[23]

Lyons and Seward

Among those members was William H. Seward, the Secretary of State. Seward would be the principal American negotiator of the treaty between the United States and Great Britain. A native of the abolitionist hotbed of Rochester, New York, he was among the most adamantly anti-slavery members of Lincoln’s cabinet. Seward ran for the 1860 Republican nomination for president. In a famous campaign speech touting his anti-slavery credentials, he called slavery “intolerable, unjust, and inhuman.”[24] While Seward did not win the nomination, he would keep his anti-slavery ideals with him when he joined Lincoln’s Cabinet.

Seward primarily negotiated with Richard Lyons, the British Ambassador to the United States. Lyons, too was opposed to slavery, leaving him—while his country maintained a veneer of neutrality—predisposed to distrusting the Confederate cause. Indeed, he wrote that “The taint of Slavery will render the cause of the South loathsome to the civilized world.”[25] Given their mutual opposition to slavery, he and Seward were the perfect pair to forge the American and British alliance that would ultimately bring the international slave trade down.

Secret Negotiations

When Lyons first presented Seward with the draft of a treaty, the American was lukewarm in his reception. He told Lyons that Union efforts in the war would quickly be successful, lowering the need for ships in the blockade and making some available for patrolling Africa.[26] A week later, however, Seward changed his mind, bur with a caveat. He would be willing to sign a treaty almost identical to the one that Russell proposed, so long as it appeared as though the proposal came from the United States, not from Great Britain.[27] His reasoning for doing so was political. Seward told Lyons that he showed the treaty to Lincoln and his cabinet, all of whom agreed to it. He then showed it to influential members of the Senate, who would have to ratify it if it were to be successful. They argued that, while most of the Senate was opposed to the slave trade, because of “the old jealousy of Great Britain on the Subject of Right of Search,” many members would not support the treaty if it appeared that it was planned by Great Britain. If it were the other way around, however, the Senate would approve.[28]

Seward remained focused on getting the treaty ready to pass through the Senate. He emphasized the need to hurry process along, so that the final treaty would be ready while American anti-slavery sentiment was still high. He feared that if the war continued to drag on, the American people might not be as supportive.[29] He also included a clause that allowed either party to terminate the treaty in ten years. While he acknowledged to Lyons that he and his anti-slavery allies in the Senate would prefer the treaty not have such a clause, he included it because he felt that it might appease certain reluctant Senators.[30] For their part, the British were willing to cooperate with Seward’s schemes. “Mr. Seward’s long experience in the Senate, and his well-known tact in dealing with that Body,” Lyons wrote, “gives his opinion…so much weight, that I naturally thought it prudent to be guided by it.”[31] Russell called it “immaterial,” whether the treaty appeared to have been proposed by the British or the Americans, given “that the object of Her Majesty’s Government [was] the suppression of the Slave Trade.”[32]

Following Seward’s pressure to have the treaty done as soon as possible, Lyons and Seward signed it on April 7, 1862. Aside from the inclusion of the clause allowing for its termination and a slight grammatical change, the treaty was identical to the one that Russell originally proposed.[33] The treaty solved the issue of the right of mutual search by allowing either of the two nations to search the ships of the other that were suspected of being involved in the slave trade. It also set up three “mixed courts of justice” made up of an equal number of British and American judges located in New York, Sierra Leone, and the Cape of Good Hope.[34] Through an act of political genius by Seward and national humility by Lyons, the last protection for slave traders had been destroyed.

Ratification and Approval by the President

The treaty was ratified unanimously by the Senate and President Lincoln signed it on June 7. Its passing left those involved in the negotiations full of optimism. The New York Times summarized Russell’s presentation of the treaty to the House of Lords as saying that “[the treaty] afforded the best evidence of the sincerity of feeling and purpose for the suppression of the slave trade, which, since the election of the current President, had characterized the Government of the United States.”[35]  Lincoln, in his annual address to Congress, said that the treaty “has been put into operation with a good prospect of complete success.”[36]

Perhaps the highest praise came from Seward himself, who was proud of his role in the treaty that he felt would “bring the African slave trade to an end immediately and forever.”[37] In a note to Lincoln congratulating him on the ratification by the Senate, he referred to the treaty as “the most important act of your life and of mine.”[38]

The anti-slavery press also greeted the treaty with optimism that it meant the end of the slave trade. The New York Times itself editorialized that, with the treaty’s passing, “The slave-trade has received its death blow.”[39] The London News called it “fresh proof of [the Lincoln Administration’s] sincerity in that hostility to Slavery which the party that raised it to power has always proclaimed to be the first article in its creed.”[40]

Enforcing the Treaty and Ending the Trade

The Senate Appropriations

The Senate quickly moved beyond just approving the treaty, showing that they took seriously the task of carrying it out. On June 13, Charles Sumner, a Radical Republican senator from Massachusetts who was among the Senate’s most anti-slavery members, proposed a bill to enforce the new treaty.[41] The bill was passed by the Senate on June 26, the House on July 8, and was signed into law by Lincoln on July 11.[42] It granted the president the authority to nominate judges to the three courts set up by the treaty, allocated a $2,500 salary for each of these judges, and repealed any previous laws “inconsistent with the stipulations of the treaty…”[43]

The End of the Atlantic Slave Trade

In the end, the British-American mixed courts never actually heard a case, although as one scholar has argued, “that was more a measure of the effectiveness of the Anglo-American treaty than its weakness, since the slave trade was squelched in the immediate aftermath of the 1862 treaty.”[44] Indeed, in his 1863 report, John Usher, the new Secretary of the Interior, wrote that “so successful have been the efforts of this Government to prevent citizens of the United States from engaging in [the slave trade], that not a single vessel is known or believed to have been fitted out in our own waters for that purpose during the past year.”[45]

Those who had predicted that the Lyons-Seward Treaty would cause the downfall of the slave trade were correct. Spain finally passed an anti-slave trade law in 1866, ending the trade to Cuba, and it is believed that the last slave ship to cross the Atlantic landed in Cuba in 1867.[46]


As Seward and Lyons were dealing a blow to the global slave trade, the United States was beginning to end the institution of slavery within its borders. In April of 1862, the same month that the Anglo-American treaty was signed, slavery was abolished in the District of Columbia. Not long after, President Lincoln issued the Emancipation Proclamation, and Congress eventually ratified the Thirteenth Amendment to the Constitution, legally ending chattel slavery in the United States. In five long and bloody years, the largest slave society in the world had come to an end.

While slavery would continue in the Western Hemisphere for a few decades after it ended in the United States, slavery in the United States and the global slave trade each reached their endings in the early 1860s. This is no coincidence. It was during this time that the U.S. government finally set out to ensure that the country was playing its part in ending the slave trade. To do this, the U.S. carried out a concerted attack on the slave trade that eventually culminated in a treaty establishing the right of search with Great Britain. After hundreds of thousands of enslaved people were torn from their homes and brought across the Atlantic to lives of toil and bondage in the Western Hemisphere, the slave trade was over.

[1] Leslie Bethell, “The Mixed Commissions for the Suppression of the Transatlantic Slave Trade in the Nineteenth Century,” in Journal of African History 7, no. 1 (1966), 79-83.

[2] “An Act to Prohibit the Importation of Slaves into any Port or Place Within the Jurisdiction of the United States, From and After the First Day of January, in the Year of our Lord One Thousand Eight Hundred and Eight,” March 2, 1807.

[3] Thomas Jefferson, “Sixth Annual Message,” December 2, 1806.

[4] “Act of 1820,” May 15, 1820.

[5] “Webster-Ashburton Treaty,” August 9, 1842.

[6] Brazil outlawed the slave trade in 1850, so in the decade leading up to the American Civil War, slavers only took their human cargo to Havana. For more on the abolition of the Brazilian slave trade, see Jeffrey Needel, “The Abolition of the Brazilian Slave Trade in 1850: Historiography, Slave Agency, and Statesmanship,” in Journal of Latin American Studies vol. 33, no. 4 (2001), 681-711.

[7] Matthew Karp, This Vast Southern Empire: Slaveholders at the Helm of American Foreign Policy (Cambridge: Harvard University Press, 2016), 25-26.

[8] “Republican Party Platform,” May 17, 1860.

[9] James Oakes, Freedom National: The Destruction of Slavery in the United States, 1861-1865 (New York: W.W. Norton, 2013), 22-34

[10] “The Republican Party Platform,” 1860.

[11] Abraham Lincoln, “Inaugural Address,” March 4, 1861.

[12] Caleb Blood Smith, “Report of the Secretary of the Interior,” November 30, 1861 in Message of the President of the United States to the two houses of Congress, at the commencement of the second session of the thirty-seventh congress, Vol. 1 (Washington: Government Printing Office, 1861), 453.

[13] “The Slaver Erie.”, The New York Times, October 10, 1860.

[14] “The Slave Trade—The Conviction of Capt. Gordon of the Slaver ‘Erie’,” The New York Times, November 9, 1861.

[15] E. Delafield Smith to Montgomery Blair, November 19, 1862, in Abraham Lincoln papers: Series 1. General Correspondence. 1833 to 1916.

[16] Abraham Lincoln, “Proclamation granting Nathaniel Gordon a temporary stay of execution,” February 4, 1862 in Abraham Lincoln papers: Series 1. General Correspondence. 1833 to 1916.

[17] Rhoda E. White to Abraham Lincoln, February 17, 1862, in Abraham Lincoln papers: Series 1. General Correspondence. 1833 to 1916.

[18] “The Execution of Nathaniel Gordon,” The New York Times, February 22, 1862.

[19] Ibid.

[20] Gideon Welles, “Report of the Secretary of the Navy,” December 2, 1861 in Message of the President of the United States to the two houses of Congress, at the commencement of the second session of the thirty-seventh congress, Vol. 1 (Washington: Government Printing Office, 1861), 615.

[21] Amanda Foreman, A World on Fire: Britain’s Crucial Role in the American Civil War (New York: Random House, 2010), 172-198.

[22] Russell to Lyons, February 28, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 516-17.

[23] Russell to Lyons, March 1, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 518.

[24] William H. Seward, “The Irrepressible Conflict,” October 25, 1858, Rochester, New York.

[25] Richard Lyons quoted in Eugene Berwanger, The British Foreign Service and the American Civil War (Lexington: The University Press of Kentucky, 1994), 28.

[26] Lyons to Russell, March 15, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 519.

[27] Lyons to Russell, March 21, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 519.

[28] Lyons to Russell, March 25, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 519-520.

[29] Ibid.

[30] Lyons to Russell, March 28, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 522.

[31] Lyons to Russell, March 31, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 523.

[32] Russell to Lyons, April 10, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 524-25.

[33] Lyons to Russell, April 7, 1862, in A. Taylor-Milne “Documents—The Lyons-Seward Treaty of 1862,” The American Historical Review 38, no. 3 (April 1933), 523-24.

[34] “Treaty between United States and Great Britain for the Suppression of the Slave Trade,” April 7,1862.

[35] “The New Slave-Trade Treaty,” The New York Times, June 5, 1862.

[36] Abraham Lincoln, “Annual Message of the President,” December 1, 1862 in Message of the President of the United States to the two houses of Congress, at the commencement of the third session of the thirty-seventh congress, Vol. 1 (Washington: Government Printing Office, 1862), 4.

[37] Seward to Adams, April 8, 1862 in Message of the President of the United States to the two houses of Congress, at the commencement of the third session of the thirty-seventh congress, Vol. 1 (Washington: Government Printing Office, 1862), 65.

[38] Seward to Lincoln, April 24, 1862 in Abraham Lincoln papers: Series 1. General Correspondence. 1833 to 1916.,0.091,1.597,1.313,0

[39] “The New Slave-Trade Treaty,” The New York Times, May 2, 1862.

[40] The London News, Reprinted in “The Lyons-Seward Treaty,” The New York Times, May 22, 1862.

[41] Congressional Globe, 37th Congress, 2nd Session 2692 (1862).

[42] Congressional Globe, 37th Congress, 2nd Session 2941 (1862); Congressional Globe, 37th Congress, 2nd Session 3167 (1862); Congressional Globe, 37th Congress, 2nd Session 3245 (1862).

[43] “An Act to carry into Effect the Treaty between the United States and Her Britannic Majesty for the Suppression of the African Slave-Trade,” July 11, 1862 in Public Acts of the Thirty-Seventh Congress of the United States ,531.

[44] Jenny S. Martinez, The Slave Trade and the Origins of International Human Rights Law (New York: Oxford UP, 2012), 80.

[45] John Usher, “Report of the Secretary of the Interior,” December 5, 1863. Reprinted in The New York Times, January 10, 1864.

[46] Herbert S. Klein, The Atlantic Slave Trade, 2nd ed. (New York: Oxford University Press), 197.