South Carolina railroad executive James Gadsden offered Antonio López de Santa Anna $50,000,000 ($1,359,509,422.48 in 2012 money) to buy Lower California and portions of Tamaulipas, Nuevo Leon, Coahuila, Chihuahua, and Sonora. The purchase would resolve the dispute over the Mesilla Valley, prime railroad land, open a route including that valley to stretch a railroad from New Orleans by way of El Paso to the Gulf of California. He presented his offer on September 25, 1853.
The purchase would give the South its preferred avenue to connect the West Coast to the rest of the nation and almost certainly additional slave states. The new railroad might even spur movement of slaveholders and their human property into California, strengthening the movement to divide the free state in two. The additional land might not just reverse the South’s 1850 loss of the Senate, but return a brief Southern majority. At the very least, the nation could for a time return to the old practice of admitting states in pairs, one slave and one free.
Santa Anna needed the money. The area suffered Indian raids from over the border that he could not do much about. The sparse population and lack of local Mexican authority made northwestern Mexico prime real estate for filibustering, which both William Walker and the French consul in San Francisco noted with intense interest. But Santa Anna already signed one treaty giving over large sections of his country to the United States. Mexicans, like most other people, did not welcome the dismembering of their nation. To a battlefield humiliation in the recent past, Gadsden asked Santa Anna to add a second defeat at the diplomat’s pen. Santa Anna refused to sell.
Seeing that Santa Anna needed the money, but would not surrender so much territory, Gadsden made a second offer. For $15,000,000, the United States would purchase just land south of the Gila River, between the Rio Grande and Colorado, including a port on the Gulf of California. Gadsden told Santa Anna that they lived in an age of adventure when bold men would surely stage secession movements in the Mexican north. A smart man would sell. And by the way, the United States does not support or condone the activities of William Walker or others…but these things do happen. Santa Anna reached out to the British to intervene. The Court of St. James demurred.
Very well, the United States could have land south of the Gila, up very close to but not including the shore of the Gulf of California. If the Americans wanted a railroad to end there, they could have their commerce run through a Mexican port. Santa Anna signed on December 30, 1853 and the treaty went to the White House, where the Cabinet debated it in January. They wanted considerably more land than Santa Anna would give, and the lack of a port must have especially stung, but finally sent it to the Senate.
The Constitution requires the Senate to ratify treaties by a 2/3 majority, thirty votes in 1854. The treaty got twenty-seven. For the first time in the body’s history, it refused to take land offered to it. Divisions that only hinted in 1848 when Trist overstayed his instructions and delivered less land than the expansionists wanted came to the fore. Antislavery senators wanted no land, seeing it as virgin frontiers for slavery. Intense lobbying by railroad interests further tainted the treaty.
Quite aside from refusing the land, the treaty marked a new blossoming of sectionalism. Though the railroad might touch on slavery indirectly, it previously stood apart as an issue in its own right. It did no longer. The Senate finally ratified a treaty that gave the United States nine thousand square miles less for five million less on April 25.