In 1787, delegates to the Constitutional Convention gathered to create a new government for the United States. As delegates debated the proposed constitution, they were forced to compromise on several issues, including representation in the proposed bicameral legislature. While each state would receive equal representation in the Senate, two members per state, the number of seats in the House of Representatives would be determined by population. Although enslaved people were considered property and did not have any personal rights or liberties, the compromise counted of each state’s enslaved population for the purposes of representation and taxation. This provision bolstered population counts for states that allowed slavery and increased their number of representatives in the legislature and Electoral College, as well as codified racial inequality in the Constitution.

The Haitian Revolution was the largest and most successful slave rebellion in the Western Hemisphere. The rebellion took place on the French island colony of Saint Dominigue (today known as Haiti). The colony was extremely profitable due to its widespread use of enslaved labor in the production of sugar, coffee, indigo, and cotton. In 1791, inspired by the French Revolution, the enslaved, led by a formerly enslaved man named Toussaint l’Overture, rebelled against the planter class. By 1792, the rebels controlled a third of the island. After several years of sustained conflict, l’Overture’s forces managed to briefly conquer the neighboring Spanish colony of Santo Domingo (today known as the Domincan Republic). The conflict formally ended on January 1, 1804, when France recognized the nation’s independence and the former colony was renamed Haiti. It was the first predominantly black nation in the Western Hemisphere to declare independence from a colonial power.

On February 12, 1793, Congress enacted the first Fugitive Slave Act, requiring each state to return fugitive slaves to their owners. This law also applied to states that had outlawed slavery. Although this legislation went into effect nationwide, many northern states willfully choose not to enforce it. Some even enacted new laws to ensure that in the event of capture fugitive slaves received a jury trial.

In spring 1800, an enslaved blacksmith named Gabriel, who lived on his owner Thomas Prosser’s plantation in Henrico County, Virginia, began planning a slave rebellion. With the help of several accomplices, Gabriel spread word throughout the area and by August, they had recruited at least 150 people to launch a nighttime attack on Richmond. They planned to capture the Virginia State Armory and Capitol and hold Governor James Monroe hostage. However, the rebellion failed. Two co-conspirators, Pharoah and Tom, confessed the plot to their owner Mosby Sheppard, who then alerted the governor on August 30, 1800.

Monroe ordered the militia to patrol the city and safeguard the caches of arms and ammunition. A torrential downpour delayed the start of the insurrection, and as word spread about the patrols, Gabriel’s followers fled or went into hiding. Over the course of the next two days, Virginia militiamen terrorized hundreds of enslaved people near Richmond by breaking into and searching the quarters of anyone suspected of conspiring with Gabriel. More than seventy enslaved individuals were arrested and charged, and twenty-six were executed.

In 1820, Congress was wracked by extreme sectional tension over the issues of statehood and the federal government’s role in restricting the expansion of slavery. Initially, in 1819, the House of Representatives passed legislation to create the state of Missouri with the Tallmadge Amendment attached, which prohibited slavery in the new state. The Senate rejected the bill and the status of Missouri statehood remained unresolved. The following year, Maine also requested statehood, so Speaker of the House of Representatives Henry Clay proposed a skillful compromise, admitting Maine as a free state and Missouri as a slave state. Another provision prohibited slavery north of the 36°30’ parallel (the exception to this rule was the state of Missouri). While the compromise briefly mollified sectional tension, it continued to grow over the course of the next four decades, eventually resulting in the Civil War.

On August 21-22, 1831, an enslaved preacher named Nat Turner from Virginia sparked the deadliest slave revolt in United States history. Turner and his followers killed about sixty people, including the gruesome slaughter of ten school children. White militia forces quickly rallied in response, killing around 100 enslaved and free black individuals and capturing forty-eight others. Twenty-eight were convicted and eighteen were hanged, including Turner. Slave owners had long feared a rebellion of this magnitude. While the revolt sparked discussions among Virginians about manumission, the state passed and enforced new restrictions on slave movement, tightened its control of enslaved communities, and rejected a peaceful end to slavery.

On August 4, 1835, an enslaved man named Arthur Bowen drunkenly stood in the bedroom doorway of his owner, Anna Thornton, with an axe. The event exacerbated racial animosity that was growing due to economic and demographic changes in the city. Members of the free black community in Washington, D.C. were viewed by whites as competition for jobs and property, as they had successfully established thriving churches, organizations, and businesses. On August 12, a violent crowd targeted Beverly Snow, a free African-American man who owned a restaurant called The Epicurean Eating House. The mob ransacked his restaurant and destroyed several black schools before order was restored. Following the riot, restrictive Black Codes went into effect in an attempt to limit the rights of free African Americans in the nation’s capital.

On May 26, 1836, the House of Representatives passed the Pinckney Resolutions, a series of legislative measures infamously known as the “gag rule,” barring discussions of slavery in that chamber. The gag rule went into effect despite emphatic resistance from former president and Massachusetts Representative John Quincy Adams. As the roll call vote was taken to pass the legislation Adams shouted, “I hold the resolution to be a direct violation of the Constitution of the United States.” Adams continued to resist until the gag rule was repealed on December 3, 1844.

On June 27, 1839, a Spanish cargo schooner called The Amistad departed Havana, Cuba with fifty-three Africans illegally captured from Sierra Leone. During the voyage, the African captives revolted, killed the captain, and took possession of the ship. On August 26, The Amistad was discovered near Long Island and all individuals on board were taken to the District Court of Connecticut. The case became a rallying cause for the abolitionist movement, garnered national attention, and eventually went to the Supreme Court. Former president and staunch supporter of abolition, John Quincy Adams, masterfully argued the case before the Supreme Court on behalf of the African captives. The court ruled that the Africans were free people and the surviving individuals returned home in 1841.

In 1846, President James K. Polk instigated the Mexican-American War, a two-year conflict stemming from the 1845 annexation of Texas. Believing that the expansion of the continental United States was both preordained and justified, an ideology known as Manifest Destiny, President Polk sent American diplomat John Slidell to secretly negotiate a dispute over Texas’ boundary claims and purchase the territories of New Mexico and California for up to $30 million. When Mexican president José Jaoquín Herrera refused Slidell’s offer, President Polk ordered American troops under General Zachary Taylor to invade and occupy disputed territory, inciting the conflict.

On April 25, 1846, Mexican troops defended their territory and fired on American troops; Congress declared war shortly thereafter. American military leaders won a series of victories against the Mexican army, culminating in General Winfield Scott’s capture of Mexico City, the nation’s capital in September 1847. In 1848, the United States and Mexico signed the Treaty of Guadalupe Hidalgo. Under the treaty’s terms, the United States paid Mexico $15 million and acquired the lands of present-day California, Nevada, and Utah, as well as parts of Arizona, New Mexico, Oklahoma, Colorado, Texas, and Wyoming. Although the United States won the war, the issue over whether slavery would spread to these new territories continued, eventually resulting in the Civil War.

In 1846, the city of Alexandria, which was originally part of the District of Columbia, was ceded back to the state of Virginia by Congress. Four years later, when the Compromise of 1850 abolished the slave trade in Washington, D.C., traders simply crossed the Potomac River and continued to sell enslaved people in Alexandria.

This compromise resulted in a series of measures meant to disarm sectional conflict and resolve several legal and territorial issues surrounding the institution of slavery. The crisis began when the territory of California requested to be admitted to the Union in 1849 with a state constitution prohibiting slavery. Congress passed a series of bills in response that were bundled as the Compromise of 1850. First, Congress admitted California to the Union as a free state, which threatened to upend the equilibrium of slave and free states. Second, Texas agreed to cede territory to the federal government to create the states of New Mexico and Utah in exchange for debt relief. Slavery was not mentioned in either of these new territories, leaving the question to the states to decide for themselves. Third, the slave trade was outlawed in the District of Columbia. Finally, Congress passed a strengthened Fugitive Slave Act.

Passed as part of the Compromise of 1850, this strengthened Fugitive Slave Act dictated that any individual found harboring an enslaved person faced criminal prosecution, and slave owners were given the authority to forcibly apprehend or return runaways regardless of whether the runaway was in a slave or free state. In addition, fugitives were barred from testifying on their own behalf in court and were not permitted to a trial by jury. Previous legislation related to fugitive slaves primarily ceded the power of enforcement to the states. The updated legislation required the active intervention of the federal government to help slave owners regain control of their enslaved people. The Fugitive Slave Act was later repealed on June 28, 1864.

Introduced by Illinois Senator Stephen Douglass and signed into law by President Franklin Pierce on May 30, 1854, the Kansas-Nebraska Act repealed the Missouri Compromise of 1820. According to that compromise, slavery was prohibited north of the 36⁰30’ parallel. However, under this new legislation, the slave or free status of federal territories would instead be determined by popular sovereignty. This meant that the residents of each territory would decide upon the issue of slavery for themselves. In response to the act, proslavery and antislavery forces rushed to the territory of Kansas, resulting in an outbreak of violence infamously known as “Bleeding Kansas.” The incident signaled a prelude to the Civil War.

On March 6, 1857, the United States Supreme Court ruled in a 7-2 decision that an enslaved man named Dred Scott was not entitled to his freedom even though he and his wife, Harriet, had resided in the free state of Illinois and the free territory of Wisconsin for four years before returning to the slave state of Missouri. Chief Justice Roger B. Taney’s opinion of the ruling stated that African Americans were unable to sue in federal court because they were not citizens according to the United States Constitution. The court also argued that the 1820 Missouri Compromise was in fact unconstitutional, therefore permitting the expansion of slavery to all territories of the United States. Although the ruling was initially a devastating blow to abolitionists, it galvanized support for the movement in the long term. Some northern politicians decried the decision and defied the ruling while many southern representatives applauded the judgement, deepening sectional tensions which ultimately erupted in the Civil War four years later.

On the night of October 16, 1859, an abolitionist named John Brown led a group of nineteen men to Harpers Ferry, Virginia. In the early morning hours of October 17, Brown seized the federal armory and captured prominent citizens of the town. Brown had hoped that the raid would turn into a slave insurrection, believing the enslaved would rally to join the cause and that the weapons captured at the arsenal could be distributed throughout the countryside. Brown miscalculated his support and by that afternoon, United States Marines under the command of Colonel Robert E. Lee stormed the engine house where Brown had barricaded himself. Many of Brown’s men were killed and Brown was captured. After a quick trial, Brown was charged with treason against the state of Virginia, murder, and inciting a slave insurrection. He was hanged on December 2, 1859. Although the raid was unsuccessful, the incident further enflamed sectional tensions as some northerners touted Brown as a martyr, while southerners widely denounced his actions and the violence of abolitionists.

On April 12, 1861, Confederate forces fired upon South Carolina’s Fort Sumter, sparking the Civil War, a conflict produced by longstanding sectional tensions over the issue of slavery. The bloody four-year conflict claimed between 625,000 and 750,000 lives as the Union fought the Confederacy. The Union Army was ultimately victorious, and the Army of Northern Virginia officially surrendered on April 9, 1865, at Appomattox Court House, effectively ending the war. The Union victory also set the stage for the states to ratify the Thirteenth Amendment, abolishing the institution of slavery in the United States of America.

Congress passed “An Act for the Release of Certain Persons Held to Service or Labor in the District of Columbia” and it was signed into law by President Abraham Lincoln on April 16, 1862. Although the bill did not use the words “slave,” “slavery,” or “emancipation,” it freed approximately 3,000 enslaved people in the District and allowed slave owners to receive compensation for their enslaved people. The measure was a huge victory for the enslaved people of the nation’s capital, and the act served as a policy test for the federal government to gauge public reaction on a national scale.

On September 22, 1862, President Abraham Lincoln issued a preliminary Emancipation Proclamation following the Battle of Antietam. In this earlier version, Lincoln stated that enslaved people would be freed in rebellious states on January 1, 1863, unless the Confederate States ceased their rebellion. When the Confederacy refused to yield, President Lincoln issued the Emancipation Proclamation on January 1, 1863. It declared, “all persons held as slaves within any State or designated part of a State, the people wherof shall be then, thenceforward and forever free.” The proclamation only applied to the states that had seceded from the Union and permitted slavery to continue in the loyal border states of Missouri, Kentucky, Delaware, and Maryland. However, the Emancipation Proclamation changed the meaning of the Civil War. From Lincoln’s perspective, the Civil War was no longer just about preserving the Union; it was also about freeing the four million enslaved people of the United States.

This amendment to the United States Constitution, ratified on December 6, 1865, officially ended the institution of slavery in the United States: “Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall be duly convicted, shall exist within the United States, or any place subject to their jurisdiction.” Historically, the language in this amendment has allowed states to continue to force incarcerated individuals to work without pay.

This amendment to the United States Constitution was ratified on July 9, 1868. It granted citizenship to “all persons born or naturalized in the United States,” including formerly enslaved people. It also forbid states from depriving, “any person of life, liberty, or property, without due process of law; nor deny any person within its jurisdiction the equal protection of the laws.”

This amendment to the United States Constitution was ratified on February 3, 1870: “The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude.” Despite its ratification, African-American voters were continuously disenfranchised through the use of Black Codes, poll taxes, literacy tests, and violence.