Editing Gadsden Purchase (section)

== Treaty of Guadalupe Hidalgo ==
{{Main|Mexican Cession}}
[[File:Antonio Lopez de Santa Anna c1853.png|thumb|right|President and General [[Antonio López de Santa Anna]], photo circa 1853]]
The [[Treaty of Guadalupe Hidalgo]] (1848) ended the Mexican–American War, but left issues affecting both sides that still needed to be resolved: possession of the [[Mesilla Valley]], protection for Mexico from Indian raids, and the right of transit in the [[Isthmus of Tehuantepec]].

=== Mesilla Valley ===
The treaty provided for a joint commission, made up of a surveyor and commissioner from each country, to determine the final boundary between the United States and Mexico. The treaty specified that the boundary, after following the Rio Grande River from the sea, would turn west from the river {{convert|8|mi|km|spell=in}} north of El Paso. The treaty was based on an 1847 copy (the Disturnell Map) of a twenty-five-year-old map which was incorporated into the treaty. However, surveys revealed that El Paso was {{convert|36|mi|km}} further south and {{convert|100|mi|km}} further west than the map showed. Mexico favored the map, but the United States put faith in the results of the survey. The disputed territory involved a few thousand square miles and about 3,000 residents; more significantly, it included the Mesilla Valley. Bordering the Rio Grande River, the valley consisted of flat desert land measuring about {{convert|50|mi|km}}, north to south, by {{convert|200|mi|km}}, east to west. This valley was thought to be essential for construction of a transcontinental railroad using a southern route.<ref>{{harvp|Kluger|2007|p=491}}.</ref>

[[John Russell Bartlett|John Bartlett]] of [[Rhode Island]], the United States negotiator, agreed to allow Mexico to retain the Mesilla Valley by setting the point at which the boundary commenced toward the west from the Rio Grande River at 32° 22′ N. This point was north of the American claim of 31° 52′ N and, at the easternmost part, also north of the Mexican-claimed boundary at 32° 15′ N, both also on the Rio Grande River<ref>{{cite book |url=https://books.google.com/books?id=p_T9BS3hHzkC&pg=PA57 |title=The Treaty of Guadalupe Hidalgo: A Legacy of Conflict |first=Richard |last=Griswold del Castillo |page=57 |publisher=University of Oklahoma Press |date=1990 |access-date=May 28, 2011 |isbn=978-0806122403}}</ref>). Bartlett's agreement to 32° 22′ N was in exchange for a boundary westward from the river that did not turn north until 110° W in order to include the Santa Rita del Corbe Mountains (sometimes referred to simply as the Corbe Mountains) located in current New Mexico east of current-day Silver City. This area was believed to have rich [[copper]] deposits, and some [[silver]] and [[gold]] which had not yet been mined. Southerners opposed retention of the Mesilla Valley by Mexico because of its implication for the railroad, but President Fillmore supported it. Southerners in Congress prevented any action on the approval of this separate border treaty and eliminated further funding to survey the disputed borderland. [[Robert B. Campbell]], a pro-railroad politician from [[Alabama]], later replaced Bartlett. Mexico asserted that the commissioners' determinations were valid and prepared to send in troops to enforce the unratified agreement.<ref>{{harvp|Kluger|2007|pp=491–492}}; {{harvp|Roberson|1974|p=171}}.</ref>

=== Native American raids ===
[[File:James Buchanan.jpg|thumb|[[United States Secretary of State|U.S. Secretary of State]] [[James Buchanan]] (1791–1868), who later became 15th [[President of the United States]] (1857–1861)]]

Article XI of the Treaty of Guadalupe Hidalgo contained a guarantee that the United States would protect Mexicans by preventing cross-border raids by local [[Comanche]] and [[Apache]] tribes. At the time the treaty was ratified, Secretary of State [[James Buchanan]] had believed that the United States had both the commitment and resources to enforce this promise.<ref name="Kluger1">{{harvp|Kluger|2007|p= 492}}.</ref> Historian [[Richard Kluger]], however, described the difficulties of the task:

{{blockquote|Comanche, Apache, and other tribal warriors had been punishing Spanish, Mexican, and American intruders into their stark homeland for three centuries and been given no incentive to let up their murderous marauding and pillaging, horse stealing in particular. The [[United States Army|U. S. Army]] had posted nearly 8,000 of its total of 11,000 soldiers along the southwestern boundary, but they could not halt the 75,000 or so native nomads in the region from attacking swiftly and taking refuge among the hills, [[butte]]s, and [[Arroyo (watercourse)|arroyo]]s in a landscape where one's enemies could be spotted twenty or thirty miles away.<ref name="Kluger1" />}}

In the five years after approval of the Treaty, the United States spent $12 million (equivalent to ${{formatprice|{{inflation|US-GDP|12000000|1859|r=-7}}}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}) in this area, and General-in-Chief [[Winfield Scott]] estimated that five times that amount would be necessary to police the border. Mexican officials, frustrated with the failure of the United States to effectively enforce its guarantee, demanded reparations for the losses inflicted on Mexican citizens by the raids. The United States argued that the Treaty did not require any compensation nor did it require any greater effort to protect Mexicans than was expended in protecting its own citizens. During the Fillmore administration, Mexico claimed damages of $40 million (equivalent to ${{Formatprice|{{inflation|US-GDP|40000000|1854|r=-8}}}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}) but offered to allow the U.S. to buy-out Article XI for $25 million (${{Formatprice|{{inflation|US-GDP|25000000|1854|r=-7}}}}{{inflation-fn|US-GDP}}) while President Fillmore proposed a settlement that was $10 million less (${{Formatprice|{{inflation|US-GDP|10000000|1854|r=-7}}}}{{inflation-fn|US-GDP}}).<ref name="Kluger1" />

=== Isthmus of Tehuantepec ===
During negotiations of the treaty, Americans had failed to secure the right of transit across the {{convert|125|mi|km|adj=mid|-wide}} [[Isthmus of Tehuantepec]] in southern Mexico. The idea of building a railroad here had been considered for a long time, connecting the Gulf of Mexico with the Pacific Ocean. In 1842 Mexican President Antonio López de Santa Anna sold the rights to build a railroad or canal across the isthmus. The deal included land grants {{convert|300|mi|km}} wide along the right-of-way for future colonization and development. In 1847 a British bank bought the rights, raising U.S. fears of British colonization in the hemisphere, in violation of the precepts of the [[Monroe Doctrine]]. United States interest in the right-of-way increased in 1848 after the gold strikes in the [[Sierra Nevada]], which led to the [[California Gold Rush]].<ref name="Roberson p. 182. Kluger p. 493">{{harvp|Roberson|1974|p=182}}; {{harvp|Kluger|2007|p=493}}.</ref>

[[File:Isthmus of Tehuantepec-aeac.jpg|thumb|Isthmus of Tehuantepec in southern Mexico]]
The Memphis commercial convention of 1849 recommended that the United States pursue the trans-isthmus route, since it appeared unlikely that a transcontinental railroad would be built anytime soon. Interests in Louisiana were especially adamant about this option, as they believed that any transcontinental railroad would divert commercial traffic away from the Mississippi and New Orleans, and they at least wanted to secure a southern route. Also showing interest was Peter A. Hargous of New York who ran an import-export business between New York and [[Veracruz (city)|Vera Cruz]]. Hargous purchased the rights to the route for $25,000 (equivalent to ${{inflation|US-GDP|25000|1849|r=-5|fmt=c|cursign=$}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}), but realized that the grant had little value unless it was supported by the Mexican and American governments.<ref name="Roberson p. 182. Kluger p. 493" />

In Mexico, topographical officer [[George Wurtz Hughes|George W. Hughes]] reported to Secretary of State [[John M. Clayton]] that a railroad across the isthmus was a "feasible and practical" idea. Clayton then instructed [[Robert P. Letcher]], the minister to Mexico, to negotiate a treaty to protect Hargous' rights. The United States' proposal gave Mexicans a 20% discount on shipping, guaranteed Mexican rights in the zone, allowed the United States to send in military if necessary, and gave the United States most-favored-nation status for Mexican cargo fees.<ref>{{harvp|Kluger|2007|pp=493–494}}; {{harvp|Roberson|1974|p=182}}.</ref> This treaty, however, was never finalized.

The [[Clayton–Bulwer Treaty]] between the United States and the United Kingdom, which guaranteed the neutrality of any such canal, was finalized in April 1850. Mexican negotiators refused the treaty because it would eliminate Mexico's ability to play the US and Britain against each other. They eliminated the right of the United States to unilaterally intervene militarily. The United States Senate approved the treaty in early 1851, but the Mexican Congress refused to accept the treaty.<ref name="Kluger2">{{harvp|Kluger|2007|p=494}}.</ref>

In the meantime, Hargous proceeded as if the treaty would be approved eventually. [[Judah P. Benjamin]] and a committee of New Orleans businessmen joined with Hargous and secured a charter from the Louisiana legislature to create the Tehuantepec Railroad Company. The new company sold stock and sent survey teams to Mexico.<ref>{{harvp|Roberson|1974|p=182}}.</ref> Hargous started to acquire land even after the Mexican legislature rejected the treaty, a move that led to the Mexicans canceling Hargous' contract to use the right of way. Hargous put his losses at $5 million (equivalent to ${{Formatprice|{{inflation|US-GDP|5000000|1850|r=-6}}}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}) and asked the United States government to intervene. President Fillmore refused to do so.<ref name="Kluger2" />

Mexico sold the canal franchise, without the land grants, to A. G. Sloo and Associates in New York for $600,000 (equivalent to ${{Formatprice|{{inflation|US-GDP|600000|1850|r=-6}}}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}). In March 1853 Sloo contracted with a British company to build a railroad and sought an exclusive contract from the new [[Franklin Pierce]] Administration to deliver mail from New York to San Francisco. However, Sloo soon defaulted on bank loans and the contract was sold back to Hargous.<ref>{{harvp|Kluger|2007|pp= 494–495}}.</ref>