 Greetings from the National Archives. I'm David Ferriero, Archivist of the United States and it's my pleasure to welcome you to today's virtual book talk with Alice Baumgartner, author of South to Freedom. Before we begin, I'd like to tell you about two upcoming programs you can view on our YouTube channel. On Tuesday, February 9th, at 1 p.m. Alex Tresniowsky will tell us about his new book, The Rope, which recounts the investigation into the murder of a 10-year-old girl in 1910 and how it helped launch the National Association for the Advancement of Colored People. And on the following Tuesday, February 16th, at noon, Robert P. Watson will discuss his book, George Washington's Final Battle. Watson describes how our first president tirelessly advocated for a capital on the shores of the Potomac and provides a historical lesson in leadership and consensus building. In her introduction to South to Freedom, Alice Baumgartner relates an encounter she had in Mexico City while doing research for this book. When a man asked her where she was from and she replied she was American, he reminded her that everyone on that subway was American. We often forget that the name America applies to the lands of the entire Western Hemisphere and American history need not be confined to the borders of the United States. Baumgartner's new book, South to Freedom, directs our attention to our nation's southern border and the actions of thousands of people seeking freedom from slavery. Their acts of self-emancipation and southerners' reactions to those acts intensified the antebellum sectional crisis and endangered the fraught balance between northern and southern states. South to Freedom gives us a new perspective on the state of the Union before the Civil War and the causes of the Civil War. By reminding us that the journey to freedom did not always lead north, Alice Baumgartner helps us understand the continental scope of this critical chapter of our history. Alice Baumgartner is an assistant professor of history at the University of Southern California. She holds a PhD from Yale University and a degree in Latin American studies from the University of Oxford where she was a Rhodes Scholar. Her article The Line of Positive Safety won the Lewis Peltzer Award from the Organization of American Historians and the Bolton Cutter Prize from the Western History Association. South to Freedom was selected as an editor's choice by the New York Times Book Review and as one of the best black history books of 2020 by the African American Intellectual History Society. Now let's hear from Alice Baumgartner. Thank you for joining us today. Thank you so much to the National Archives for inviting me to be part of this series. I did a lot of work for this book out of the National Archives in DC, College Park in Fort Worth, Texas and I really couldn't have done that work without all of the archivists who helped me find materials and the archivists who preceded them who helped to catalog them. So it's especially gratifying to be able to share the results of that research now in this series. I had to admit though that I never really expected to study runaway slaves who escaped to Mexico in the decades leading up to the US Civil War, the topic of my book. In the summer of 2012, I was doing research in northeastern Mexico on a different topic, on violence on the US-Mexico border in the 19th century. I was expecting to find a lot of evidence of filibustering and know not the type that congressmen do now to delay bills. Filibustering of the rioting that US citizens did in the mid 19th century to further the cause of quote-unquote manifest destiny, the idea that the United States was destined to span from the Atlantic to the Pacific. And I found plenty of evidence of US citizens invading places like Mexico in pursuit of manifest destiny. But I also found evidence of another more unexpected type of violence, slavery from the United States attempting to kidnap there enslaved people who had escaped to Mexico and facing both legal and violent resistance from Mexican authorities. At the time, I didn't know that local Mexican authorities were using the law on violence to protect enslaved people. I didn't even know that enslaved people were escaping to Mexico. But the more research I did, the more evidence I found that enslaved people were escaping to the south. Some received help from free blacks, ship captains, male writers, and other quote lurking scoundrels. But most escaped to Mexico by their own ingenuity. They forged travel passes. They prayed to their gods bearing bones beneath their doors to protect them on their journey. They stole horses, firearms, skiffs, for hats, and in one instance, 12 gold watches and a diamond breastpin. And then they disappeared. Their stories have, for the most part, disappeared too. Reconstructing this history requires in-depth research on both sides of the border. This project took me to 27 different archives in three different countries. Some of those archives were so out of the way that I was written up in the local newspaper for going. But the main reason that this story has been overlooked is that U.S. historians assume that neither Mexico's government nor its citizenry was particularly committed to anti-slavery and that Mexico's anti-slavery policies buckled easily under pressure from the United States. If the promise of freedom in Mexico was illusory, then fugitive slaves escaping across the Rio Grande was a small local story without broader implications for our understandings of abolition in the Americas. The problem with this conclusion, as I learned over the course of my research, was that the Mexican government did not, in fact, retreat from its anti-slavery position under pressure from the United States. Mexico's Congress abolished slavery in 1837, but it didn't stop there. Much to the consternation of its neighbors, it adopted a constitution in 1857 that promised freedom not just to slaves within Mexico, but to the slaves of other countries from the moment they set foot on the national soil, a promise known as the Freedom Principle. Writing this guarantee into Mexico's constitution signaled that the Freedom Principle was not a legal doctrine to be invoked or ignored as the circumstances required, but a general and inviolable principle written into the law of the land. Mexico's laws were no radical than those passed by the Northern States and Canada. The Northern States had, of course, either abolished slavery or passed gradual emancipation laws, but the fugitive slave clause of the U.S. Constitution and the laws that were passed to enforce it prevented those states from promising freedom to all enslaved people who set foot on the soil like Mexico did, and that meant that the promise of freedom could not legally extend to enslaved people in neighboring states. Similarly, slavery had been abolished in the British Empire, including Canada in 1833, and while Canadian authorities didn't work to try to protect enslaved people who crossed into Canada, they continued to extradite criminals to the United States, criminals who sometimes happened to be fugitive slaves, as in the case of one runaway who was returned to his owner in 1842 for having stolen a beaver overcoat, a racing mare, and a gold watch while escaping from Arkansas. The only nation in the Americas with anti-slavery policies as radical as Mexico's was the former French colony of San Bamanque, which revolted in 1791 and founded the Republic of Haiti. Haiti abolished slavery in 1804 and adopted the freedom principle in 1816, although Haiti's anti-slavery policies destabilized slavery in Cuba and Jamaica, and although it struck fear in the hearts of southern slaveholders, the island lay 500 miles by sea from the southernmost tip of Florida. Mexico, by contrast, directly bordered the U.S. South. This proximity of spaces of mass-travel slavery meant that Mexico's anti-slavery policies would have profound consequences for its neighbors, especially when war broke out between Mexico and the United States in the mid-19th century. In 1846, as U.S. congressmen debated the status of slavery in the territories that they stood to acquire from Mexico, northerners of both political parties, both Whigs and Democrats, balked at the prospect of re-establishing slavery where it had been prohibited. Abolition in Mexico does undermine the norm of admitting slavery in southern territories while prohibiting it in northern ones, a norm that had kept sectionalism at bay since the Missouri Compromise of 1820. The escape of enslaved people into Mexico is a small window into a much bigger story, and today I want to tell three parts of that story. First, of Mexico's rise as an anti-slavery public, second of the ways in which abolition shaped the lives of enslaved people in the U.S.-Mexico borderlands, and third, the forgotten significance of Mexican abolition to slavery in the United States. By showing how Mexican abolition altered the geography of freedom for enslaved people in Texas and Louisiana, and how it provoked a major congressional controversy in the United States, I hope to offer a new perspective on the history of anti-slavery in the Americas, and of early national Mexico's forceful intervention into that history. On September 16, 1829, President Vicente Guerrero, himself of African descent, celebrated Mexico's 8th Independence Day with an act of, quote, justice and charity. He decreed an end to slavery across the country, and historians often date abolition in Mexico to Guerrero's decree, a policy that they argue passed largely without comment, because black slavery was simply no longer important to Mexico's national economy. Slavery had taken root in New Spain at the end of the 16th century after a series of epidemics decimated the indigenous population, and the Portuguese were granted a monopoly or asiento to supply the Spanish colonies with African slaves. As we can see in this chart here of the enslaved population in New Spain, between 1580 and 1640, there's a huge influx of African slaves to New Spain, and in fact, New Spain imported more African slaves than any other colony in the western hemisphere except Brazil. But a drop in sugar prices in the end of the Portuguese asiento put black slavery on a path of decline, and we can see that decline here in the enslaved population. By the time that Mexicans took up arms against Spain in 1810, black slaves numbered only 9 to 10,000. At the same time that Mexico's enslaved population was declining, anti-slavery sentiment was on the rise, and there are a couple of reasons why we see anti-slavery sentiment rising in this period. The first is that the war against Spain, Mexico's independence movement, had forged a link in the popular imagination between slavery and colonialism, individual emancipation, and national independence. Enslaved people reinforced this connection in the 1820s in Puebla in central Mexico, an enslaved man named José Muñoz petitioned for his freedom on the grounds that slavery could not exist in a newly independent republic. 300 miles to the north in Guadalajara, the enslaved people belonging to a man named Doni Ciro Gonzales made the exact same argument, and this is just one of many examples of the ways in which enslaved people, by their individual actions, contributed in important ways to larger political changes. The second reason that we see anti-slavery on the rise in the early national period in Mexico is that championing anti-slavery helped to distinguish Mexico from Spain, an important task for any fledgling government. While Spain continued to permit human bondage and its colonial possessions particularly in the island of Cuba, anti-slavery helped Mexico to cast itself in a different, more enlightened mold. Third, anti-slavery helped Mexico to differentiate its independence movement from its more renowned forbear, the American Revolution. Mexican politicians predicted that the Americans' uprising would be forgotten because of the contradiction between its professed ideals of liberty and equality and the millions of people enslaved in its fields. Mexico's independence movement, by contrast, would make good on its rhetoric of liberty and equality. The anti-slavery sentiment in Mexico manifested itself most clearly at the state level. From 1821 to 1827, seven of Mexico's 19 states abolished slavery outright and you can see them highlighted here in blue. These nine other states also decreed that the children born of enslaved people would be free, what was known as a free wound law and they were highlighted here in pink. These laws, of course, did not abolish slavery, at least the free wound law didn't. But like the gradual emancipation laws adopted in states like Pennsylvania, Connecticut, Rhode Island, New York, and New Jersey, these laws did guarantee that human bondage would eventually come to an end. Given the declining enslaved population and the popular enthusiasm for anti-slavery is not unreasonable to assume, as historians have, that President Geddo's decree in 1829 abolishing slavery would have been welcomed and applauded, but the opposite happened. From the sugar producing south came predictions of economic ruin. Slave holders in Chiapas, which you see highlighted here, demanded immediate compensation. The town council of Córdoba Veracruz warned that the decree would cause the ruin of this population that labors exclusively in the cane fields. Meanwhile, Yucatan seceded from the Mexican confederation. Its legislature lambasting the national government for assuming powers that rightly belong to the states. Among its grievances was the abolition of slavery, a cruel attack on property that the legislators insisted, disadvantaged Yucatan more than any other state. The Anglo-American colonists who famously were settling in the Mexican province of Tejas, claimed the same distinction. The threat of a revolt among these colonies was in fact so great that President Geddo accepted the province from his degree. But these protests would soon become moot because in 1831, Mexico's Congress abrogated all the laws, decrees, regulations, ordinances, and orders that Geddo had issued, including the decree abolishing slavery. The revocation of Geddo's decree meant that slavery did not end in 1829, and the protests over the decree suggest that the decline of black slavery did not in fact guarantee its end. If Mexico's anti-slavery laws were not simply the result of a declining slave population, then when and why was slavery actually abolished in Mexico? Although slavery was declining nationally, it remained important regionally. It's hard to give exact numbers of where the enslaved population was focused after independence, because the Mexican government, when it declared its independence from Spain, had abolished distinctions of caste, and census takers had stopped recording racial categories on censuses. And this is a good example of a post-independence census from 1827, which records the name, the age, the work, whether or not someone knew how to write, but nothing about race or ethnicity. So we have to rely on anecdotal evidence, and that evidence suggests that the remaining enslaved population of Mexico was concentrated in two regions, the sugar producing south where we'd seen a lot of resistance to Geddo's decree, and also in the Khan producing north in the Anglo-American colonies of Tejas. The Mexican government could not abolish slavery immediately across the entire nation without risking a revolt in these two slave holding regions. But I think what's important really to emphasize here is that just because the Mexican government didn't abolish slavery outright, that doesn't mean that it was complicit in or condoning human bondage forever. As we talked about, state governments had taken really important measures against slavery, and the national government was also making its own inroads against the peculiar institution. In particular, in 1824, the national government forbade any enslaved person from being imported into Mexico, a law that posed a major threat to those Anglo-American colonists immigrating to the Mexican colony of Tejas with ambitions of using enslaved labor to grow cotton. Both state and national laws in Mexico posed a threat to the future of slavery in that country. Anglo colonists had learned to circumvent these laws, particularly the law against the importation of slaves, by enforcing enslaved people to sign indentured contracts for periods of up to 90 years, in other words, a lifetime contract to labor. But on April 28th, 1832, the legislature of Coahuila y Tejas, the state to which the province of Tejas was attached, passed a law that limited the terms of any contract to 10 years and invalidated any previous contracts that had been signed for a longer period of time. Suddenly, those lifelong indentures that slaveholders had forced their enslaved people to sign were annulled. Within months, enslaved people started to claim their freedom under this new law. In the spring of 1832, enslaved people, Peter and his son John, escaped from the Anglo-American colonies in eastern Tejas to San Antonio de Bejar. After gaining an audience with the mayor of San Antonio, they petitioned for their freedom on the grounds that they had been imported to Mexico in violation of its prohibition against the slave trade. In 1834, an enslaved woman named Minerva also claimed her freedom, this time before the U.S. District Court of Western Louisiana, on the grounds that her owner had taken her from Arkansas into Tejas in violation of Mexico's laws. That same year, in 1834, Mexico's vice president dispatched a secret agent to Tejas with instructions, quote, to seek by every possible and prudent means to make it known to the slaves who have been brought to the republic in the circumvention of the law, that the law gives them freedom by the mere act of stepping on the territory of the republic, close quote. As more enslaved people filed suit for their freedom and Mexican officials redoubled their efforts to enforce the ban on the importation of slaves, the Anglo colonists in Tejas concluded what they had long suspected, that their rights would never be safe under Mexican rule. Texan's ability to circumvent anti-slavery legislation was even further diminished when President Antonio López de Santa Ana overturned Mexico's federalist constitution in favor of a more centralist system of government in which he could impose laws on the states without their consent. In the fall of 1835, the Anglo colonists in Tejas took action against this political change and revolted. And less than a year later, on April 21, 1836, Texas forces defeated the Mexican army at the Battle of San Jacinto, securing independence of Texas, at least for the moment. The Mexican government planned to launch another expedition to reconquer Texas, and so it came as a surprise and an affront when on March 3, 1837, a mere 10 months after the Texas revolution, the U.S. government recognized Texas's independence. The U.S. authorities insisted that their decision recognized by law what Texas had established in fact. The republic had formed a stable government with regular elections, even a circulating currency, which we can see here. Now, this diplomatic recognition might seem not particularly important, but when we think of a recent headline that the Palestinians recognized Texas as a part of Mexico, it really shows that this issue continues to be of profound importance. Just kidding, fake news, that didn't actually happen. But it shows us that this is something that is important, that even though diplomatic recognition doesn't mean that the United States was sending arms and weapons to Texas, that that diplomatic recognition alone granted the Republic of Texas a certain status within the community of nations that undermined Mexico's claims to retake its seceded colony. Six weeks after the Van Buren administration recognized Texas independence, Mexico's Congress voted to abolish slavery without exception. And the timing of abolition in Mexico is really no coincidence. The secession of Texas eliminated the largest slaveholding state from the Mexican Federation, and because the Texans had revolted, the Mexican government was under no obligation to compensate those citizens for any loss, so the financial costs of implementing abolition were smaller than before. Moreover, the benefits appeared greater. Defending liberty acted on popular anti-slavery sentiment in Mexico, and we can kind of see an expression of that anti-slavery sentiment in this playbill for you might recognize that this is a play version of Harriet Beecher Stowe's famous novel, Uncle Tom's Cabin, a very, very successful play produced in Mexico. It was for building upon that anti-slavery sentiment that had been in development since the 1820s. And that anti-slavery sentiment was even more important now in the wake of the Texas revolution, because it allowed Mexicans to sort of find victory and defeat. Texans, for all of their talk of liberty and the rights of man, state's rights, were, according to Mexicans, destroying the true liberty of humanity by enslaving black people. The United States might boast of its successes, as did the Republic of Texas, but only in Mexico could stand upright before the world. This position also galvanized international support from Mexico, from Edinburgh, Scotland, to Westchester, New York. Anti-slavery societies condemned Texas as a quote-unquote loathsome republic that had exercised its political liberty in defense of slavery. And again, this image of the eagle of liberty, the free eagle of Mexico grappling the cold-blooded viper, tyranny, or Texas really encapsulates that feeling that was prevalent, particularly among anti-slavery leaning people, that the Texas revolution was unjustified and that Mexico truly was in the right. The abolition of slavery bolstered morale among Mexicans and a galvanized support for Mexico, but it also served a larger political purpose. A number of enslaved people had fled from their masters before, during, and after the Texas revolution, and this flight helped to convince the Mexican government that by revolt or escape, enslaved people had the power to destroy the fledgling republic of Texas when it most needed to gain the respect of the international community, although it had been recognized by the United States no other country had followed suit. And they were hoping that maybe there was a slave revolt that perhaps further international recognitions would not be forthcoming. As news of Mexico's abolition policy spread, Texans complained that their enslaved people displayed a very refractory disposition, and they blamed the Mexican government for sending emissaries, quote, to excite an insurrection. You can see here in this article from the Telegraph in Texas Register. Not only did abolition promise to help return Texas to the Mexican Federation, it also posed an obstacle to U.S. expansion. The U.S. government made no secret of its ambition to acquire part, if not all, of Mexico's territory. But if slavery were abolished in the lands that southern adventurers hoped to acquire from Mexico, then the Mexican authorities believed that their neighbors would have to turn their tensions elsewhere. The United States' slaveholding empire could not extend into non-slaveholding Mexico. To reestablish slavery where it had previously been abolished, in the words of Mexico's Minister of Foreign Affairs in 1848, violated the reigning, quote, philosophical principles of the civilized world. If enslaved people resisted their masters using what scholars call weapons of the weak, breaking tools, feigning illness, working slowly, minor ways in which they could resist their enslavement, governments could also resist in these furtive ways. Mexico's anti-slavery policies were a powerful weapon in the hands of a weak government. They weren't overtly belligerent. The northern states in Canada had also abolished slavery. But these measures boosted morale, attracted international support, recruited military alanis by encouraging enslaved people to revolt or escape, and discouraged further U.S. expansion. They were, in the words of one Mexican diplomat, quote, the rock that could shatter the clay foot of the United States. After Mexico abolished slavery, enslaved people responded by escaping in increasing numbers across the border into Mexico. Two options awaited most runaways in Mexico. The first was to join Mexico's military colonies, a series of outposts along Mexico's northern frontier which defended against native peoples and foreign invaders. Most fugitive slaves joined one particular military colony in northern Coalila, a state in Mexico's northeast, where the Seminole Indians and their black allies started settling beginning in 1815. And we can see a picture of black Seminole scouts here. Life in Mexico was not easy. Few fugitive slaves spoke Spanish. As a senate of one remembered in an interview with historian Kenneth Wiggins Porter in 1942, we couldn't even ask for a chaw of tobacco. Most had so little taste for Mexican food that they scraped the red beans from the tortillas that their neighbors handed them. And the demands of military service, perhaps most importantly, constrained their autonomy. Fathers, husbands, and sons had to take up arms at a moment's notice. But this military service also earned the fugitive slaves respect from Mexican authorities who praised them for their desire, quote, to succeed in punishing the enemy. Mexican authorities recognized that the very people, the very filibusters that they were trying to protect against, were the very people who sometimes were seeking to re-enslave those escaped slaves. For all of its restrictions, military service also helped fugitive slaves defend themselves against those who wished to return them to slavery. On September 20th, 1851, Sheriff John Crawford of Bear County, Texas, rode 200 miles from San Antonio to the Mexican military colony in Coahuila, where most of these enslaved people had settled. There he arrested two men he suspected of being runaways and carried them across the Rio Grande. Jose Antonio de Arredondo, a justice of the peace in Guerrero Coahuila, insisted that the two men were both, quote, under the protection of our laws and government and considered as Mexican citizens, close quote. When US officials explained that a court in San Antonio had ordered their arrest, the sub-inspector of Mexico's eastern military colonies demanded that they be released. Meanwhile, a force of black and seminal people attempted to cross the Rio Grande and free the prisoners by force. Though military service helped to ensure the freedom of former slaves, that freedom came at a cost, risk to one's life and the heat of battle, and participation in Mexico's brutal campaign against native peoples. But not every runaway joined the colonies. Some settled in cities like Monterey, which you can see pictured here, or Matamoros, which had a growing black population of merchants and carpenters, bricklayers and manual laborers, hailing from Haiti, the British Caribbean, and the United States. Others didn't go to cities. They hired themselves out to local landowners who were in constant need of extra hands. Evaristo Madero, a businessman who carted goods from Saltillo, Mexico to San Antonio, Texas, hired two black domestic servants. Espirillón Gomez employed several others on his ranch near San Fernando. These were who he has encountered a different set of challenges than those who joined the military colonies. Those who worked on haciendas and in households were often the only people of African descent on the payroll, leaving them no choice but to assimilate into their new communities. Most learned Spanish, and many changed their names, as did one former slave named Dan, who in Mexico called himself the Onicio de Chevarilla. Fugitive slaves also encountered labor practices that bore some of the homers of chattel slavery. In northern Mexico, hacienda owners enjoyed the right to physically punish their employees, meeting out corporal punishment as harsh as any on plantations in the United States. And parts of southern Mexico, such as Yucatán and Chiapas, that peonage tied laborers to plantations as effectively as violence. But in contrast to the United States, where enslaved people in the south knew no other law beside the whim of their owners, laborers in Mexico enjoyed a number of legal protections. These workers could file suit when their employers lowered their wages or added unreasonable charges to their accounts. They could also sue in cases of mistreatment as Juan Castillo of Galeana Nuevo León in northeastern Mexico did in 1860, after his employer hit him, whipped him, and ran him over with a horse. His employer admitted to quote, an excess of anger. In general, laborers had the right to seek new employment for any reason, a right that was of course denied to enslaved people in the United States. But in contrast to the antebellum United States, fugitive slaves could and did become citizens of Mexico. A former slave named John was elected to serve on the municipal jury of Musquiz, Colila in 1858, a duty reserved for citizens. Santos, another black man in Musquiz, served as a deputy for a local judge, a gun of responsibility for citizens alone. This was important because as historian Stephen Cantrowitz reminds us, 19th century African Americans demanded not just freedom from slavery, but also belonging, political citizenship. And perhaps the greatest proof of that belonging was the links that Mexicans would go to defend the former slaves who had become their neighbors. On August 20th, 1850, Manuel Luis del Fiero stepped outside his house in Reynosa Tamolipas, a town just across the border from McAllen, Texas. And you can see a slightly later image of the Plaza principal in Reynosa. The night was hot and a band was playing in the plaza. And as he stood listening to the music, two foreigners approached asking if he wanted to join them on the plaza. Del Fiero politely refused their invitation. And he didn't really give the incident much thought until later that night when he woke to the sound of a woman screaming. Del Fiero hurried toward the commotion. In one of the rooms of the house, he came across the two foreigners who invited him to the concert earlier. One of them was waving a pistol at his maid, Matilda Hennes, who quote, had been held as a slave in the United States, as Del Fiero later testified. Hennes had belonged to a planter named William Cheney, who owned a plantation near Cheneyville, Louisiana, a town 150 miles northwest of New Orleans. When Solomon Northrop, a free black man who was kidnapped from the north and sold into slavery, arrived at a plantation in a neighboring parish, he heard that several enslaved people had been hanged in the area for planning, quote, a crusade to Mexico, close quote. As Northrop recalled in his memoir, 12 Years of Slave, the plot was, quote, a subject of general and unfailing interest in every slave hut on the bayou, close quote. From her years working on Cheney's plantation, Hennes must have known that Mexico's laws would give her acclaimed freedom. At some point, when her house was unclear, Hennes acted on that knowledge, escaping from Cheneyville, making her way to Reynosa, and finding work in Manuel Luis Del Fiero's household. To Del Fiero, Matilda Hennes was not just a runaway. As a servant, she was a member of his household. In the room where she was battling out with these slave holders, Del Fiero took hold of his gun, while his wife called for help from the balcony. One of the kidnappers who was arrested turned out to be Hennes's former owner, William Cheney. In Mexico, Cheney found that he could not treat people of Africanist descent with impunity, as slaveholders often did in the United States. While Cheney sat in prison, Judge Jufe de Trevino of the District of Northern Tamaulipas began an investigation into the attempted kidnapping. Del Fiero's actions were not unusual. In 1851, the townspeople of a small village in Northern Coelhila took up arms, quote, in the service of humanity, close quote, to stop a slave catcher named Warren Adams from kidnapping a black family. Later that year, the Mexican army posted a respectable force and two artillery pieces on the Rio Grande to stop a group of 200 Americans from crossing the river, likely to see his fugitive slaves. In 1852, four townspeople from Guerrero Coelhila chased after a slave holder from the United States who had kidnapped a black man from their colony. They found the slave holder who pulled out a six-shooter, but one of the townspeople drew faster, killing the man. Unable to bring the kidnapper to court, the councilman brought his corpse to the judge of Guerrero, who certified that he was in fact dead, quote, for not having responded when spoken to in other cadaverous signs, close quote. The protection that Mexican citizens provided was significant because the national authorities in Mexico City did not have the resources to enforce many of the country's most basic policies. Mexico's anti-slavery laws might have been a dead letter, in other words, if not for those ordinary people of all races who risked their lives to protect fugitive slaves. As Mexico became known as a refuge for runaways, the landscape of slavery in the south-central United States began to shift. Perspective immigrants chose not to settle in south Texas, quote, for the unsafety of bringing slaves, close quote. Point Isabel to the mouth of a Rio Grande was deemed by most immigrants to be, quote, non-slave holding due to its proximity to Mexico, close quote. Slave holders in Texas and Louisiana were so concerned by the number of enslaved people escaping to the south that diplomats from the United States were instructed to pressure the Mexican counterparts to sign an extradition treaty that would return fugitive slaves to their owners. But negotiations for such a provision failed in 1850, 1851, 1853, 1857. Mexico's extradition of fugitive slaves, according to the US Secretary of State, would not be entertained, quote, for a moment, close quote. And we can really see the effect of this in this census from Brownsville, Texas in 1860, where we list the names of slave holders and the number of slaves that they owned. And in column six, you can see the list of those enslaved people who were, quote, unquote, fugitives from the state. We can see here that four out of the seven enslaved people in Brownsville, Texas, just on the border with Mexico, were escaped, presumably to Mexico. The freedom that Mexico promised with threatened slavery, not just in the nearby states of Texas and Louisiana, but also at the very heart of the Union. The trouble began in 1845 when the United States annexed the Republic of Texas. And that debate only accelerated a year later when the United States provoked a war with Mexico. President James K. Polk, who was in charge of the United States during this war, made clear that he intended to pay for the conflict by seizing Mexico's territories. And the question soon became what the status of slavery in those conquerors' territories would be. On August 8, 1846, several months after the start of the Mexican-American War, a U.S. congressman from Pennsylvania named David Wilmot proposed that slavery be excluded from any territory that the United States might acquire from Mexico. The so-called Wilmot proviso threw the issue of slavery into the center of the political arena, leading historian Eric Foner to argue, rightly, I think, that the introduction of the Wilmot proviso was the event in U.S. history, quote, that seemed to lead almost inevitably to sectional controversy and civil war, close quote. Despite its significance, the Wilmot proviso remained something of a puzzle. Why was a proviso that was never adopted so controversial? And why would someone like David Wilmot, a Northern Democrat who had never given any sign of anti-slavery convictions, make such a proposal in the first place? Historians had proposed a number of explanations, which I'd be happy to talk about more in the Q&A, but none are as compelling as the argument that Northern Democrats themselves made, which was that the federal government had no power to interfere with slavery where it existed. It was for that reason that David Wilmot had supported the annexation of Texas as a slave state in 1845, because as he explained, quote, slavery had already been established there, close quote. If the federal government lacked the power to abolish slavery where it existed, as in Texas, then Wilmot argued it also lacked the power to establish slavery where it had been abolished, as in Mexico. Since the Mexican government had abolished slavery in 1837, Wilmot argued that any land ceded to the United States after the Mexican American War would enter the Union as free territories. Wilmot insisted that this proviso was not an anti-slavery measure. Instead, he claimed that his proviso promised to do only what, quote, the gentleman from the South asked, to let slavery alone. Southern congressmen, many of whom have long argued against federal interference of any variety with slavery, nonetheless refused to accept Wilmot's reasoning, because the Wilmot proviso threatened to upset the delicate balance of power between North and South. If the territories ceded from Mexico were recognized as free territories, then basically all of the remaining territories in the West would be closed to slavery. Mexican abolition, in other words, forced the U.S. Congress to make what seemed like an impossible choice, either to admit the former Mexican territories as free states, which would destroy the balance of power between North and South in D.C., particularly in the Senate. As you can see here, blue states are red states, red states are slave-holding states. Or they could argue for re-establishing slavery, where it had been previously abolished, which would help to maintain that sectional balance, as you can see in option number two, but would create a dangerous precedent for federal intervention with respect to slavery. Northern politicians who had no particular desire to support slavery weren't about to reverse their long-standing convictions that the federal government should be limited in order to defend that political balance between North and South. Southern politicians, for their part, really didn't want to choose between those two options. Instead, they blustered that Mexico could not possibly have abolished slavery. It is a way to kind of avoid having to choose between these two options. Senator John Berrien of Georgia argued that Mexico's federal government had no more right than its U.S. counterpart to abolish slavery. He said, quote, I understand the Mexican confederation to have been formed upon the model of our own, and that the power over the subject of slavery belonged to the separate states of the Mexican Republic, close quote. In other words, he's saying the Mexican Congress couldn't possibly have abolished slavery in 1837 because their constitution didn't allow them to. This was incorrect, but he was insistent anyway. Congressman William Henry Brockenbrough of Florida pointed to, quote, the servitude of poor debtors of all races to the wealthy, which was more profitable to the master and less comfortable to the slaves. He's arguing that all of those ways in which coercion continued in Mexico meant that slavery really did continue, even though it was legally abolished, and that the southern states didn't have to recognize the abolition of slavery as a result. Northerners deemed these arguments hardly admissible. Senator James Shields of Illinois scoffed that, quote, the people of Mexico will be highly edified when they learn that their old acquaintances, the Norte Americanos, had discovered that slavery was in full force in operation in that country without the people themselves being aware of that fact. I think when they hear this, they will come to the conclusion that we are as invincible in logic as we are in battle, close quote. To prove once and for all that slavery had been abolished. Congressman started to read the laws of Mexico on the floor of the Congress. Representative Henry C. Murphy of New York borrowed a collection of Mexican laws from the State Department Library to read before the House, and Senator Thomas Hart Benton took things one step further. He read Mexico's laws in the original Spanish, reading from this law digest here. Ninguno es esclavo en el territorio de la nación, Benton read. Another congressman complained, quote, the Senate cannot understand a word of what he reads. The introduction of the Wilma proviso turned the slow burn of sectionalism into a blaze. But Senator Thomas Hart Benton saw a simple solution to the disputes caused by Mexico's abolition of slavery. Benton was, of course, the representative from Missouri, which was a slave state. He argued that if Mexico's laws prohibiting slavery remained enforced in the ceded territories, that the Wilma proviso was redundant, unnecessary. The peculiar institution could not legally extend to the territory ceded from Mexico, proviso or no proviso. To Benton, Mexico's abolition of slavery made the proviso into, quote, a thing of nothing, an empty provision, a cloud without rain, close quote. In other words, he's saying we don't need to pass the Wilma proviso. Slavery can't extend to that session. And the people who are proposing the proviso are just trying to stir up sectional animosities. Benton's argument convinced many of those northern Democrats who had broken party lines by voting for the Wilma proviso. Richard Broadhead of Pennsylvania wondered, quote, if the territory will be free when it is annexed and Congress has no power to make it slave, where is the necessity for the adoption of the amendment, close quote. Like Benton, he's arguing we don't need the amendment because Mexican laws are still enforced. We're still respecting them. To Senator James W. Bradbury of Maine, the proviso was, quote, an unnecessary enactment, close quote. For slavery had already been as prohibited by Mexican laws as by any act of Congress. And he said, quote, these laws remain enforced. And the proviso is now there prohibiting slavery throughout their entire extent, close quote. So Congress is basically saying that they can't overturn Mexico's laws. But if Congress couldn't do that, who could? All but the most strident abolitionists believed that the territories, when admitted as states, possessed the unquestioned right to amend previous legislation, including the laws relating to slavery. Northerners assumed that slaveholders would not risk taking their enslaved people to the former Mexican territories, and that as a result, those territories would join the union as free states. But Southern whites thought that immigrants to the former Mexican territories would bring their slaves, and that they would vote to reestablish slavery in the American Southwest. So although Congress was not going to explicitly prohibit slavery in those territories, there was this question about whether Mexican laws remained enforced and how those laws could be overturned. If slaveholders believed that immigrants to the former Mexican territories would vote to reestablish slavery, they would soon be disabused of this belief. In 1849, less than a year after the end of the Mexican-American war, California petitioned for admission to the union as a free state. The bounds of power between the North and South hung in the balance. There were 15 free states and 15 slave states at the time, and the admission of California as a free state seemed to put slaveholders at a permanent disadvantage in the Senate. To put an end to the sectional controversy provoked by Mexican abolition, Senator Henry Clay of Kentucky introduced a series of resolutions on January 29th, 1850. The compromise measures would admit California as a slave state in accordance with the will of the people in the territory. But the compromise refrained from passing any legislation on the remaining territories, what would become New Mexico, Arizona, parts of Utah, and Colorado. And the compromise refrained from passing any legislation on slavery in those territories because in Clay's own words, quote, slavery does not exist by law in any of the territory acquired by the United States from the Republic of Mexico, close quote. As a result, Clay deemed it in expedient for Congress to provide by law, either for its introduction into or exclusion from any part of the said territory, close quote. Mexico's laws abolishing slavery remained in effect in its seated territories until the people voted to alter, or as in the case of California, to uphold those laws. Southern politicians had only to look at a map of the United States to realize what this meant for the sectional balance between North and South. After the admission of California, there were 16 free states and 15 slave states. And there was no guarantee that the remaining territories would enter the union as slave states. Southern politicians spent the next decade trying to revert the loss of power that the Mexican American War and Mexican abolition set in motion. Their efforts led to the failed annexation of Cuba in 1854, the overturning of the Missouri compromise also in 1854, the outbreak of violence in Kansas, and the birth of a new political party, the Republican Party, whose success in the election of 1860 led to the outbreak of the U.S. Civil War. Mexico's policies with respect to slavery had serious implications for human bondage in the United States. Mexico bordered the U.S. South, and specifically the Deep South, where slave-based agriculture was booming. Eventually, enslaved people escaped to Mexico with such frequency that Texas seemed to have more in common with the states that bordered the Mason-Dixon line. Samuel Houston, then the governor of Texas, made the states clear on the eve of the Civil War, quote, Texas is a border state, close quote, he wrote in 1860, quote, Mexico renders and secure her entire Western boundary. Her slaves are liable to escape, but no fugitive slave law is pledged for her recovery, close quote. In fact, Mexico's laws rendered slavery insecure not just in slavery in Texas and Louisiana, but at the very heart of the Union, Washington, D.C. The land seized from Mexico at the close of the Mexican-American War in 1848 was free territory. That territory included what is most of modern-day California, Nevada, Utah, New Mexico, and Arizona. When Southern politicians attempted to establish slavery in that region by popular sovereignty, they ignited a sectional controversy that would eventually lead to this assertion of the Southern states. It's easy to discount Mexico's anti-slavery stance, given that coercion continued in so many other forms in Mexico, as enslaved people who escaped there sometimes learned, but these laws were a momentous achievement nonetheless. Only by abolishing human bondage was it possible to extend the debate over the full meaning of universal freedom, the enslaved people who escaped from the United States, and the Mexican citizens who protected them, ensured that the promise of freedom in Mexico was significant, even if it was sometimes incomplete. As the poet Walt Whitman put it, quote, it is provided in the essence of things that from any fruition of success, no matter what, shall come forth something to make a greater struggle necessary, close quote. Their work, our work, is not over.