The Gadsden Purchase (known as Venta de La Mesilla, or "Sale of La Mesilla", in Mexico) is a region of present-day southern Arizona and southwestern New Mexico that was purchased by the United States in a treaty signed by James Gadsden, the American ambassador to Mexico at the time, on December 30, 1853. It was then ratified, with changes, by the U.S. Senate on April 25, 1854 and signed by President Franklin Pierce, with final approval action taken by Mexico on June 8, 1854. The purchase was the last major territorial acquisition in the contiguous United States, adding an area the size of Scotland to the United States.
The purchase included lands south of the Gila River and west of the Rio Grande. The Gadsden Purchase was for the purpose of the US's construction of a transcontinental railroad along a deep southern route. It was also related to reconciliation of outstanding border issues following the Treaty of Guadalupe Hidalgo, which ended the Mexican–American War of 1846–48.
As the railroad age progressed, business-oriented Southerners saw that a railroad linking the South with the Pacific Coast would expand trade opportunities. They thought the topography of the southern portion of the Mexican Cession was too mountainous to allow a direct route. Projected southern routes tended to run to the north at their eastern ends, which would favor connections with northern railroads and ultimately favor northern seaports. Southerners saw that to avoid the mountains, a route with a southeastern terminus might need to swing south into what was then Mexican territory.
The administration of President Franklin Pierce, strongly influenced by Secretary of War Jefferson Davis, saw an opportunity to acquire land for the railroad, as well as to acquire significant other territory from northern Mexico. In the end, territory for the railroad was purchased for $10 million ($ today), but Mexico balked at any large-scale sale of territory. In the United States, the debate over the treaty became involved in the sectional dispute over slavery, ending progress before the American Civil War in the planning or construction of a transcontinental railroad.
In January 1845 Asa Whitney of New York state presented the US Congress with the first plan to construct a transcontinental railroad. Although Congress took no action on his proposal, a commercial convention of 1845 in Memphis took up the issue. Prominent attendees included John C. Calhoun, Clement C. Clay, Sr., John Bell, William Gwin, and Edmund P. Gaines, but it was James Gadsden of South Carolina who was influential in the convention’s recommending a southern route for the proposed railroad, beginning in Texas and ending in San Diego or Mazatlán. Southerners hoped that such a route would ensure southern prosperity while opening the “West to southern influence and settlement.”
Southern interest in railroads in general, and the Pacific railroad in particular, accelerated after the conclusion of the Mexican-American War in 1848. During that war, topographical officers William H. Emory and James W. Abert had conducted surveys that demonstrated the feasibility of a railroad's originating in El Paso or western Arkansas and ending in San Diego. J. D. B. DeBow, the editor of DeBow's Review, and Gadsden both publicized within the South the benefits of building this railroad.
Gadsden had become the president of the South Carolina Canal and Rail Road Company in 1839; about a decade later, the company had laid of track extending west from Charleston, South Carolina, and it was 3 million dollars ($ today) in debt. Gadsden wanted to connect all Southern railroads into one sectional network. He was concerned that the increasing railroad construction in the North was shifting trade in lumber, farm goods, and manufacturing goods from the traditional north-south route based on the Ohio and Mississippi rivers to an east-west axis that would bypass the South. He also saw Charleston, his home town, losing its prominence as a seaport. In addition, many Southern business interests feared that a northern transcontinental route would cut the South off from trade with the Orient. Other Southerners argued for diversification from a plantation economy to keep the South independent from northern bankers.
In October 1849 a convention to discuss railroads was held in Memphis, in response to a separate convention called in St. Louis earlier in the fall, which had discussed a northern route. The Memphis convention overwhelmingly advocated the construction of a route beginning there, to connect with an El Paso to San Diego line. Disagreement arose only over the issue of financing. The convention president, Matthew Fontaine Maury of Virginia, preferred strict private financing, whereas John Bell and others thought that Federal land grants to railroad developers would be necessary.
Gadsden had supported nullification in 1831. In 1850 he advocated secession by South Carolina when California was admitted to the Union as a free state. Gadsden considered slavery “a social blessing” and abolitionists “the greatest curse of the nation.”
When the secession proposal failed, Gadsden, working with his cousin Isaac Edward Holmes, a lawyer in San Francisco since 1851, and the California state senator Thomas Jefferson Green, attempted to divide California in two. They proposed that the southern half would allow slavery. Gadsden planned to establish a slaveholding colony there based on rice, cotton, and sugar. He would use slave labor to build a railroad and highway, originating in either San Antonio or on the Red River, that would transport people to the California gold fields. Toward this end, on December 31, 1851, Gadsden asked Green to secure from the California state legislature a large land grant located between the 34th and 36th parallels; it would eventually serve as the dividing line for the two California states.
A few months after this, Gadsden and 1,200 potential settlers from South Carolina and Florida submitted a petition to the California legislature for permanent citizenship and permission to establish a rural district that would be farmed by "not less than Two Thousand of their African Domestics". The petition stimulated some debate, but it finally died in committee.
The Compromise of 1850, which created the Utah Territory and the New Mexico Territory, would facilitate a southern route to the West Coast since all territory for the railroad was now organized and would allow for Federal land grants as a financing measure. Competing northern or central routes championed, respectively, by Stephen Douglas of Illinois and Thomas Hart Benton of Missouri would still need to go through unorganized territories. A precedent for using federal land grants had been established when Millard Fillmore signed a bill promoted by Douglas that allowed a Mobile to Chicago railroad to be financed by "federal land grants for the specific purpose of railroad construction." To satisfy Southern opposition to the general principle of Federally supported internal improvements, the land grants would first be transferred to the appropriate state or territorial government, which would oversee the final transfer to private developers.
By 1850, however, the majority of the South was not interested in exploiting its advantages in developing a transcontinental railroad or railroads in general. Businessmen like Gadsden, who advocated economic diversification, were in the minority. The Southern economy was based on cotton exports, and then-current transportation networks met the plantation system's needs. There was little home market for an intra-South trade. In the short term, the best use for capital was to invest it in more slaves and land rather than in taxing it to support canals, railroads, roads, or in dredging rivers. Historian Jere W. Roberson wrote:
|“||Southerners might have gained a great deal under the 1850 land grant act had they concentrated their efforts. But continued opposition to Federal aid, filibustering, an unenthusiastic President, the spirit of "Young America", and efforts to build railroads and canals across Central America and the Isthmus of Tehuantepec in Mexico divided their forces, leaving a lot of time for the Pacific railroad. Moreover, the Compromise of 1850 encouraged Southerners not to antagonize opponents by resurrecting the railroad controversy.||”|