In Western countries, efforts to limit slavery began with the prohibition of the African slave trade and attempts to enforce an international ban on this traffic. Britain outlawed the slave trade in its possessions in 1807, and the United States soon followed suit, effective as of 1 January 1808. While the U.S. law curtailed the international supply of slaves, American traders continued to retail slaves through a domestic market. The abolitionist movement then focused on eradicating slavery itself. Antislavery activists created cooperative networks where they proselytized against slavery and abetted the escape of fugitives. Some antislavery activities had an international character. One campaign, noted in the cities of the northeastern United States and in Great Britain, focused on encouraging consumers to buy products grown without slave labor. The effort met with indifferent success but provided small ephemeral markets for imports from Haiti—a country that had gained its independence through slave rebellion—and after 1833, the British West Indies. The promotion of free labor produce coincided with a growing conviction in the northern United States and Britain that wage labor was the most rational, just, and efficient method of work, and with the social and political evolution of industrial society in those areas.
The British Parliament in 1833 enacted a gradual abolition program that ended slavery in British dominions by 1838. Between 1830 and 1860 a small African-American community had gathered in Britain. As most American universities barred black students, some were attending universities of far higher caliber than those in the United States. Others were fugitives who had made their way to a country where slavery was prohibited. Such prominent U.S. abolitionists as Frederick Douglass and Charles Lenox Remond and his sister Sarah Remond visited Britain to enlist both the working classes and the bourgeoisie in the American antislavery cause. Black abolitionists gave public lectures and sold copies of slave narratives written by themselves and others. They succeeded in thwarting many of the fund-raising efforts of the American Colonization Society, established in 1816–1817 to resettle blacks on the west coast of Africa. In Ireland, the Irish nationalist Daniel O'Connell, an outspoken foe of slavery, embraced Frederick Douglass. Douglass spent nineteen months lecturing in the British Isles between 1845 and 1847. British Quakers raised the money to buy Douglass's freedom from his Maryland owner.
Antislavery activists hoped that pressure applied by Britain, then the world's most powerful nation, would persuade the United States to deal forthrightly with the slavery question. Abolitionists did not succeed in capturing all Britons. They faced the opposition of those manufacturers and workers most dependent on imports of U.S. cotton, but benefited from a widespread revulsion among all classes against slavery. The groundwork that Douglass, the Remonds, and others laid helped neutralize British sympathies for southern slaveholders. This was a critical issue during the 1850s, when sectional animosity reached a crisis point in the United States. If Britain, despite its own antislavery stand within its realms, allied with the Confederacy during the U.S. Civil War, the United States would likely be defeated. While American abolitionists often avoided direct discussions of class conflict because of their frequent reliance on elite patronage in Britain and their desire to keep the focus on slavery, the zenith of their activity coincided with the Chartist movement, which sought to improve conditions for the industrial working class, and debates over the status of labor.
American slavery was also drawn into the international arena as a result of the activities of fugitive slaves. In the course of the nineteenth century some thirty thousand black persons from the United States entered Canada. Periods of domestic crisis, such as the passage of the Fugitive Slave Act of 1850 and the Dred Scott decision, accelerated this immigration. The Fugitive Slave Act made it easy for slaveholders and bounty hunters to threaten the liberty of free people of color. In an explicitly racist finding, the Supreme Court, in the 1857 case Scott v. Sandford, ruled that blacks could not be citizens and had no civil rights. The decision effectively ended the prospects of free people of color in the United States until after the Civil War. Many who were able left the country. In addition to the relatively familiar escapes to Canada by slaves and free people alike, blacks from Texas crossed the border into Mexico, where slavery was illegal. During the early years of the Republic, when Spain loosely administered Florida, fugitives in combination with the Seminole nation engaged the United States in wars in 1817–1818 and 1835–1842. In the aftermath of the first Seminole war, Spain, unable and unwilling to guarantee the security of U.S. real and chattel property along its Florida borders, and wishing to avoid armed conflict with Americans, ceded the rebellious territory to the United States.
Fugitives also included those whose antislavery activities put them in jeopardy of the law. Frederick Douglass in 1859 was a suspect in John Brown's conspiracy to seize the federal armory in Harpers Ferry, Virginia. Douglass fled to England to avoid arrest. Once there, he contacted the U.S. minister to the Court of St. James's hoping to secure a passport to visit France. The passport was denied on grounds that Douglass, according to Supreme Court dicta, was not a U.S. citizen. Douglass was an early victim of passport denial, a practice that would be used in the twentieth century to restrict the movements of blacks who were known critics of racial discrimination.