Foreign Pressure, American Freedom

As early as 1775, the English essayist Samuel Johnson lambasted the slaveholding revolutionaries in the 13 colonies: “How is it that we hear the loudest yelps for liberty among the drivers of negroes?”

Foreign governments could also pressure the United States through diplomatic channels. The Chinese government called on the State Department to stop mob violence against Chinese immigrants in the American West during the 19th century. The Soviet Union, perhaps more cynically, was also determined to expose the hypocrisy of U.S. claims of freedom. The U.S. branch of the Communist International, for example, helped to organize and fund the defense of the Scottsboro boys, nine African American teenagers and young men accused without evidence of raping two white women on a train in 1931.

The Mexican government was no exception, and it had more levers to pull than most other countries because of its proximity to the United States. At both inflection points in United States history—the end of slavery and the Civil Rights Movement—Mexico played an important role.

On April 5, 1837, Mexico’s Congress abolished slavery, less than a year after the Republic of Texas had won its independence from Mexico. The timing was no coincidence. Abolition afforded Mexico a kind of moral power in the wake of its defeat in the Texas Revolution. Like Johnson during the American Revolution, Mexican diplomats did not hesitate to point out that the Texas revolutionaries, for all their talk of “liberty” and “rights of man,” were destroying the “true liberty” of enslaved people. Not only did this sentiment galvanize international support for Mexico, but it also led enslaved people to escape in greater numbers across the Rio Grande, destabilizing slavery in Texas and the Mississippi, where cotton agriculture was booming.

Enslaved people escaped to Mexico by any means available. Some traveled by water, requisitioning canoes and flatboats, fashioning rafts from firewood, concealing themselves on board the ships docked at New Orleans. Most, however, escaped by land. They lurked in river bottoms, sought shelter in abandoned houses, and hid beneath overturned boats along rivers and canals. Each month, about a dozen freedom seekers reached Matamoros, across the Rio Grande from Brownsville. Two hundred and seventy arrived at Nuevo Laredo in a single year. In 1860, six of the nine slaves that the census takers tallied in Brownsville, Texas, were labeled “fugitives from the state.”

Enslavers in Texas and Louisiana were concerned by the number of enslaved people escaping to the south. Residents of Washington-on-the-Brazos, 80 miles northwest of Houston, worried in local newspapers about fugitive slaves “lurking” in the river bottoms. Rumors circulated of Mexican troops assembling on the Rio Grande to drive the Anglo upstarts out of Texas. “The frequent occurrence of the running off of our negroes is becoming so great an evil that it calls for a remedy,” wrote one citizen to the governor of Texas in 1851.

No policy could stop the flight of enslaved people across the Rio Grande. Diplomats from the United States demanded an extradition treaty that would return freedom seekers to their enslavers. But their Mexican counterparts refused to negotiate in 1850—and in 1851, 1853, and 1857. The return of fugitive slaves would not even be considered, complained the U.S. secretary of state in 1853.

Undeterred, local authorities set to work negotiating their own extradition treaties with the state governments of Coahuila and Nuevo León. When these efforts also failed, white southerners proposed annexing the states of Tamaulipas, Nuevo León, and Coahuila.

As Mexico became known as a beacon of freedom, the landscape of slavery in the south-central United States began to shift. No man “in his senses” risked bringing “a large gang of negroes south of the Colorado,” lest they escape, lamented one newspaper based in Richmond, Virginia. An English-language newspaper in Matamoros confirmed that prospective immigrants chose not to settle in South Texas for the “unsafety of bringing slaves.” The area around the mouth of the Rio Grande was declared “non-slaveholding” due to its closeness to Mexico.

Historians have argued that the antislavery movement in the northern states contributed to a growing sense among white southerners that their property rights would never be secure within the United States. The flight of enslaved people to Mexico added to their sense of embattlement. In this way, Mexico’s policies and the enslaved people who invoked them undermined slavery in the United States. The Mexican government would continue to call on the United States to live up to its founding principles in the century that followed.

The reward notice for a captured slave in the Galveston Weekly News on May 11, 1858. Stephen F. Austin State University