Opposition to slavery in British North America began in the late seventeenth century but was limited mostly to a minority of Quakers and a few Puritans until the quarter century before the Revolution. In 1754 the Quaker activist John Woolman published Some Considerations on the Keeping of Negroes, which soon stimulated a renewed hostility to slavery among Quakers. In 1758 the Yearly Meeting in Philadelphia took an official position against slaveholding, and by the time of the Revolution, most Quakers had begun to free their slaves. In 1770 Quaker leaders working with Anthony Benezet opened the African Free School in Philadelphia. Benezet published Short Account of That Part of Africa Inhabited by the Negroes (1762), which challenged common assumptions about the racial inferiority of blacks. His Some Historical Account of Guinea (1772) exposed the horrors of the African slave trade and stimulated opposition to the trade in England and America. Meanwhile, throughout the country Baptists, Mennonites, and Methodists preached against slavery. Initially, John Wesley would not even allow slave owners to join his church. Some individual Anglicans and Presbyterians also took stands against slavery, although those denominations did not oppose slavery at this time.
On the eve of the Revolution, slavery was found in all thirteen colonies and antislavery was limited mostly to the religiously motivated. The Revolution stimulated opposition to slavery from a variety of sources. Slaves, especially in New England, used Revolutionary rhetoric to challenge their own servitude, and many masters accepted these arguments and allowed their male slaves to enlist in the state militias and the Continental line in return for their freedom. By the end of the war, slavery was severely weakened in New England and Pennsylvania and under assault in New York and to a lesser extent in New Jersey. Even in the South some masters freed their slaves to serve in the army or because the masters could no longer in good faith own slaves. After the war private manumission in the South, stimulated by Revolutionary ideology or religious fervor, brought liberty to tens of thousands of slaves. In Virginia, for example, the free black population went from about two thousand in 1780 to over thirty thousand by 1810. Similarly, in Maryland the free black population went from under ten thousand in 1790 to just under forty thousand by 1820. The slave population, meanwhile, remained virtually stagnant in this period. There was also a spurt of manumissions in the Carolinas. By the War of 1812, however, the manumission rates were declining everywhere in the South except Maryland and Delaware.
In 1780, before the war was even over, Pennsylvania passed the nation's first gradual abolition act. The legislature noted the "abhorrence of that condition, to which the arms and tyranny of Great-Britain were exerted to reduce us," and declared that having been delivered from British tyranny, we conceive that it is our duty, and we rejoice that it is in our power, to extend a portion of that freedom to others, which hath been extended to us, and release from that state of thraldom, to which we ourselves were tyrannically doomed, and from which we have now every prospect of being delivered.
Similarly, Massachusetts ended slavery through its Constitution of 1780. By the end of 1784, all of the New England states had either ended slavery outright or passed gradual abolition statutes to end bondage over time. Later on, New York (1799) and New Jersey (1804) passed similar laws. Meanwhile, abolition societies sprang up throughout the North and the Upper South. Most focused on helping free blacks, abolishing the African slave trade, and ending slavery in their own states. These early antislavery advocates did not focus on ending slavery in other states, as abolitionists of the antebellum period would.
At the national level, opponents of slavery achieved two victories in the early national period. In 1787 the Congress under the Articles of Confederation banned slavery from the Northwest Territories. This ban was the result of lobbying by New England investors who wanted to purchase land in the area north of the Ohio River but did not want slavery there. The Northwest Ordinance did not immediately end slavery in the region, and there were a substantial number of slaves in Illinois and Indiana until after both territories achieved statehood. But the ordinance nevertheless showed the potency of antislavery. In 1807 Congress banned all American participation in the African slave trade, in 1819 Congress provided for stricter enforcement of the ban, and in 1820 declared that illegal importation of slaves amounted to piracy. While opponents of slavery applauded these laws, they cannot be seen solely as victories for opponents of slavery. Many slave owners, especially from the Upper South, opposed the slave trade in part because banning the trade would increase the value of their excess slaves.
The early antislavery movement began to die out after the War of 1812. By that time slavery was dead or dying in all of the northern states. Because the early societies were local in their scope and vision, they did not turn to ending slavery in the South, but instead focused on improving the circumstance and educational opportunities of free blacks in the North. Those societies that had existed in the Upper South either completely disappeared or became so marginalized that they had no effect on public policy.
In 1817 some opponents of slavery joined the newly organized American Colonization Society (ACS), which was dedicated to removing blacks from the United States. Some members of the ACS saw colonization in Africa as a way of encouraging an end to slavery, but many others hoped the movement would simply lead to the removal of the existing free black population. Sincere opponents of slavery soon abandoned the ACS and would eventually move into the abolitionist movement initiated by William Lloyd Garrison in 1831.
In 1819 Congress debated the admission of Missouri into the Union. Northern congressmen, led by James Talmadge of New York, opposed admitting Missouri as a slave state. This led to the first great debate over slavery in Congress. It led to sharp denunciations of slavery by northerners, which shocked many southern members of Congress. Never before had there been such an acrimonious debate over slavery. Sectional harmony would never again be possible as long as bondage made the nation half slave and half free.
In the decade following the Missouri debates, the issue of slavery simmered. No great antislavery movement emerged in the North, but some northerners began to speak out more directly against the system. In 1821 Benjamin Lundy began to publish the Genius of Universal Emancipation, the first bona fide antislavery newspaper in the nation. He daringly moved the paper to the South, publishing it in Tennessee, Maryland, and then Washington, D.C. In 1829 William Lloyd Garrisonjoined Lundy, and after Garrison left this partnership he began to plan for the publication of The Liberator, which in 1831 became the most important antislavery paper in the nation and the catalyst for the antislavery movement of the antebellum period.
Throughout this period African Americans were the most committed opponents of slavery. They expressed their opposition in a variety of ways. Fugitive slaves, acting as individuals or in groups, ran from bondage and in so doing expressed their opposition to slavery and their refusal to be treated as slaves. Some blacks, like the Virginia slave Gabriel Prosser and his associates, plotted rebellions. During the Revolution tens of thousands of slaves asserted their freedom or convinced their masters to free them so they could join the army, escaped from their masters, or ran away to join armies on both sides of the conflict. Thousands found refuge with the British, and some of these ended up as free people in Canada and elsewhere. Throughout the period slaves and free blacks petitioned colonial and state legislatures and the new Congress to gain their own freedom. In the 1820s black authors attacked slavery through their own publications. In 1827 Samuel Cornish and John Brown Russwurm started the nation's first blackrun newspaper, Freedom's Journal, and in 1829 Cornish began to publish his own paper, Rights of All. Most dramatically of all, in September 1829—at the very end of the period of the new American nation—David Walker published his Appeal to the Colored Citizens of the World, quoting the Declaration of Independence and demanding that blacks be given their inalienable rights to life and liberty or that they rise up in revolt, just as white Americans had done a half century earlier.