Mexican Cession.html



Region (red) ceded to the United States of America by Mexico in 1848.

The Mexican Cession of 1848 is a historical name for the region of the present day southwestern United States that was ceded to the U.S. by Mexico in 1848 under the Treaty of Guadalupe Hidalgo which ended the Mexican-American War. The treaty was signed on February 2 1848, ratified by the U.S. Senate on 10 March 1848, and by the Mexican government on 19 May 1848.

Background

The cession of this territory from Mexico was a condition for the end of the war, as United States troops occupied Mexico City, and Mexico risked being completely annexed by the U.S. The United States also paid $15,000,000 ($298,310,309 in 2005) for the land, and agreed to assume $3.25 million in debts to US citizens.¹ The land ceded by Mexico is 14.9% of the total area of the current United States territory. 1.36 million km² (525000 square miles, or 55% of its pre-war territory) was lost by Mexico.² As of July 1, 2007, the states of California, Nevada, Utah, Arizona and New Mexico had a total population of 50,072,597 out of 305,986,357 nationwide, or 16.4% of the US population.

For the 38 years between 1810 when Mexico declared its independence from Spain (or from 1821, when Mexican independence was secured), and 1848, the region had formed approximately 42% of the country of Mexico; prior to that, it had been a part of the Spanish colony of New Spain for some three centuries. Beginning in the early seventeenth century, a chain of Spanish missions and settlements extended into the New Mexico region, mostly following the course of the Rio Grande from the El Paso area to Santa Fe, which was a colonial capital under the Spanish, and which is now the capital city of the U.S. state of New Mexico. Spanish settlement and missionary work followed the course of the Colorado River northward from its mouth along the current border between California and Arizona. Beginning in the late eighteenth century, Spain had also built a system of fortresses and missions throughout Alta California (now western half of the US state of California), from San Diego to San Rafael north of San Francisco.

Territory

The region includes all of the present-day states of

• California
• Nevada, and
• Utah,

as well as portions of:

• Arizona excluding the region later annexed in the Gadsden Purchase
• Colorado west of the boundary of the former Republic of Texas
• New Mexico west of the Rio Grande and excluding the Gadsden Purchase, and
• Wyoming west of the former Republic of Texas boundary and south of the 42nd parallel.

The treaty also specified the Texas-Mexican border as being at the Rio Grande (Río Bravo del Norte). Previously the portion of Texas between the Nueces River and the Rio Grande had remained disputed throughout the existence of the Republic of Texas. The United States had already claimed the area as part of the Texas Annexation in 1845.

Subsequent organization and the North-South conflict

Soon after the war started and long before negotiation of the new US-Mexico border, the question of slavery in the territories to be acquired polarized the Northern and Southern United States in the most bitter sectional conflict up to this time, which lasted for a deadlock of four years during which the Second Party System broke up, Mormon pioneers settled Utah, the California Gold Rush settled California, and New Mexico under a federal military government turned back Texas's attempt to assert control over territory Texas claimed as far west as the Rio Grande. Eventually the Compromise of 1850 preserved the Union, but only for another decade. Proposals included:

• The Wilmot Proviso banning slavery in any new territory to be acquired from Mexico, not including Texas which had been annexed the previous year. Passed by the United States House of Representatives in August 1846 and February 1847 but not the Senate. Later an effort to attach the proviso to the Treaty of Guadalupe Hidalgo also failed.
• Failed amendments to the Wilmot Proviso by William W. Wick and then Stephen Douglas extending the Missouri Compromise line (36°30' parallel north) west to the Pacific, allowing slavery in most of present day New Mexico and Arizona, Las Vegas, Nevada, and Southern California, as well as any other territories that might be acquired from Mexico. The line was again proposed by the Nashville Convention of June 1850.
• Popular sovereignty, developed by Lewis Cass and Douglas as the eventual Democratic Party position, letting each territory decide whether to allow slavery.
• William L. Yancey's "Alabama Platform," endorsed by the Alabama and Georgia legislatures and by Democratic state conventions in Florida and Virginia, called for no restrictions on slavery in the territories either by the federal government or by territorial governments before statehood, opposition to any candidates supporting either the Wilmot Proviso or popular sovereignty, and federal legislation overruling Mexican anti-slavery laws.
• General Zachary Taylor, who became the Whig candidate in 1848 and then President from March 1849 to July 1850, proposed after becoming President that the entire area become two free states, called California and New Mexico but much larger than the eventual ones. None of the area would be left as an unorganized or organized territory, avoiding the question of slavery in the territories.
• The Mormons' proposal for a State of Deseret incorporating most of the area of the Mexican Cession but excluding the largest non-Mormon populations in Northern California and central New Mexico was considered unlikely to succeed in Congress, but nevertheless in 1849 President Taylor sent his agent John Wilson westward with a proposal to combine California and Deseret as a single state, decreasing the number of new free states and the erosion of Southern parity in the Senate.
• Senator Thomas Hart Benton in December 1849 or January 1850: Texas's western and northern boundaries would be the 102nd meridian west and 34th parallel north.
• Senator John Bell (Tennessee politician) (with assent of Texas) in February 1850: New Mexico would get all Texas land north of the 34th parallel north (including today's Texas Panhandle), and the area to the south (including the southeastern part of today's New Mexico) would be divided at the Colorado River (Texas) into two Southern states, balancing the admission of California and New Mexico as free states.³
• First draft of the compromise of 1850: Texas's northwestern boundary would be a straight diagonal line from the Rio Grande 20 miles north of El Paso to the Red River (Mississippi watershed) at the 100th meridian west (the southwestern corner of today's Oklahoma).

• The Compromise of 1850, proposed by Henry Clay in January 1850, guided to passage by Douglas over Northern Whig and Southern Democrat opposition, and enacted September 1850, admitted California as a free state including Southern California and organized Utah Territory and New Mexico Territory with slavery to be decided by popular sovereignty. Texas dropped its claim to the disputed northwestern areas in return for debt relief, and the areas were divided between the two new territories and unorganized territory. El Paso where Texas had successfully established county government was left in Texas. No southern territory dominated by Southerners (like the later short-lived Confederate Territory of Arizona) was created. Also, the slave trade was abolished in Washington, DC (but not slavery itself), and the Fugitive Slave Act was strengthened.

References