Analysis of The Mexican War as The Notion of Manifest Destiny

In order to fully understand the entirety of the Mexican War, it is important to understand the concept of Manifest destiny. Manifest destiny was a term coined by John L. O’Sullivan in 1845. This term was “the latest justification for white settlers to take the land they coveted” (370). He “called on them to resist any foreign power – British, French, or Mexican that attempted to thwart ‘the fulfillment of our manifest destiny to overspread the continent allotted by the Providence for the free development of our yearly multiplying millions…’” (370). This new term almost instantly swept over the United States, and provided them with justification for obtaining new land and territories in the west, something that the Americans believed was a “God-given right” based on “the superiority of their institutions and white culture” (370).

This idea of Manifest destiny ultimately led to the Mexican War. The Americans wanted to expand their territory to the west. Texas, who had recently gained independence from Mexico, was an interesting prospect. Unsettling to the North though, was the fact that this would add another slave state. The Democrats, in an attempt to please the Northerners, proposed expansion in to Oregon, as a free state, which would parallel to Texas being a slave state. “The United States and Britain decided in 1818 on ‘joint occupation’ that would leave Oregon ‘free and open’ to settlement by both countries” (371), but politicians were now calling for a “‘reoccupation of Oregon’” (378). This posed a threat to Britain, potentially causing another war, but manifest destiny prevailed. Polk renewed an offer with Britain, that was approved by Senate, giving the nation the territory peacefully. Along with the issue of the annexation of Texas, there was a major dispute with the borders. The Mexicans believed that the border was The Nueces River, while Texas said that it was along the Rio Grande. The placement and moving of an army along these borders only added to Mexico’s frustrations. Manifest destiny also led Polk to seek interest in California and New Mexico. Originally intending to purchase these territories, Polk decided that military force would ultimately be needed to obtain these new territories. This only added fuel to the already aggravated fire. Overall, the leading cause of the Mexican War was the idea of manifest destiny because it caused Polk to seek the annexation of Texas, along with the border disputes that came with it, and potentially buying the Mexican territories of California and New Mexico.

In Polk’s inaugural address on May 11, 1846, he discussed the annexation of Texas, his military moves, and ultimately, the rationale behind his decisions: manifest destiny. “Foreign powers should therefore look on the annexation of Texas to the United States not as the conquest of a nation seeking to extend her dominions by arms and violence, but as the peaceful acquisition of a territory once her own, by adding another member to our confederation, with the consent of that member, thereby diminishing the chances of war and opening to them new and ever-increasing markets for their products” (Polk, Inaugural Address).

Because Polk was so driven by the ideal of manifest destiny, he sought to claim Mexico’s remaining northern provinces, California and New Mexico, which only added more tension and frustrations between Mexico and the United States. He had initially sought to purchase the territories from Mexico, but the Mexicans refused to sell them to him. He was very aware of the turmoil that was happening, which gave him a glimmer of hope. “Since the 1830’s, Comanches, Kiowas, Apaches and others had attacked Mexican ranches and towns, killing thousands” (378). Polk and his administration were aware of this fact, and deduced that Mexico could no longer control its northern territories. To them, this meant that Mexico lessened their claims to these territories. The combination of these facts with Polk’s need to achieve manifest destiny caused him to deduce that military force would be needed to achieve the territories he so greatly desired.

One of the causes of the Mexican War was the annexation of Texas. According to Polk in his inaugural address, “…The Republic of Texas has made known her desire to come into our Union, to form a part of our Confederacy and enjoy with us the blessings of liberty secured and guaranteed by our Constitution” (Polk, Inaugural Address). Regardless of that fact, Mexico warned that it would regard the annexation of Texas as an act of war. “Annexing Texas to the United States risked precipitating war, for Mexico had never relinquished its claim to its lost providence” (377). The

Along with the problems that was caused by the annexation of Texas, there were disputes between the United States and Mexico regarding borders. “The Congress of Texas, by its act of 19 December 1836, had declared the Rio del Norte to be the boundary of that Republic. Its jurisdiction had been extended and exercised beyond the Nueces. The country between that river and the Del Norte had been represented in the Congress and in the convention of Texas, had thus taken part in the act of annexation itself, and is now included within one of our Congressional districts” (Polk, War Message). The United States, along with the Republic of Texas, viewed the banks of the Rio Grande as the southernmost border. Mexico, on the other hand, was under the impression that the Nueces River was the separating border. “Polk had already ordered General Zachary Taylor to march his 4,000-man army 150 miles south from its position on the Nueces River” (378). This movement was seen by Mexico as an act of aggression. To retaliate, the Mexican general in Matamoros to retreat back to the Nueces, and because he refused, the Mexicans attacked on April 25, 1846. They then killed and wounded 16n men, and captured the rest.

Polk justified the Mexican War by claiming that it was the Mexicans who initiated it. He originally had peaceful intentions. “The movement of the troops to the Del Norte was made by the commanding general under positive instructions to abstain from all aggressive acts toward Mexico or Mexican citizens and to regard the relations between that Republic and the United States as peaceful unless she should declare war or commit acts of hostility indicative of a state of war...” (Polk, War Message) In his War Message to Congress, Polk is stating that the aforementioned movement of troops was in fact peaceful. He did not intend to perform aggressive acts towards the Mexican army nor its citizens. The Mexican army did not see the movement as a peaceful one, and retaliated by killing and wounding 16 men, and capturing the rest. Once that happened, Polk declared war. “‘Mexico has passed the boundary of the United States, has invaded our territory, and shed American blood upon American soil’” (378). “As war exists, and, notwithstanding all our efforts to avoid it, exists by the act of Mexico herself, we are called upon by every consideration of duty and patriotism to vindicate with decision the honor, the rights, and the interests of our country...” (Polk, War Message). There is a lot of controversy surrounding this because “even before news of the battle arrived in Washington, Polk had obtained his cabinet’s approval of a war message” (378). It seems as if Polk wanted war regardless, because he previously had permission from his cabinet to declare war. It appears that the retaliation by Mexico was just an excuse Polk used to declare war.

Abraham Lincoln, at the time, a Whig representative from Illinois, gave a speech to Congress regarding the issues he saw within Polk’s argument and justification for war. “Before Abraham Lincoln sat down, he had questioned Polk’s intelligence, honesty and sanity” (379). In his speech, he then goes on to decipher each part of the president’s arguments for war, and stated why they are poor arguments or have no backing. “The main deception of it is, that it assumes as true, that one river or the other is necessarily the boundary; and cheats the superficial thinker entirely out of the idea, that possibly the boundary is somewhere between the two, rivers, and not actually at either-- … 1-- That the Rio Grande was the Western boundary of Louisiana as we purchased it of France in 1803-- … Now, admitting for the present, that the Rio Grande, was the boundary of Louisiana, what, under heaven, had that to do with the present boundary between us and Mexico? … 2 That the Republic of Texas always claimed the Rio Grande, as her Western boundary-- …That is not true, in fact-- Texas has claimed it, but she has not always claimed it-- … But suppose she had always claimed it-- Has not Mexico always claimed the contrary … 3 That by various acts, she had claimed it on paper-- … I mean here what he says about the fixing of the Rio Grande as her boundary in her old constitution (not her state constitution) about forming Congressional districts, counties &c &c-- Now all of this is but naked claim … 4-- That Santa Anna,3 in his treaty with Texas, recognized the Rio Grande, as her boundary-- that Santa Anna, while a prisoner of war, a captive, could not bind Mexico by a treaty … 5 -- That Texas before, and the U S. after, annexation had exercised jurisdiction beyond the Nueces -- between the two rivers-- … He tells us it went beyond the Nueces; but he does not tell s us it went to the Rio Grande-- He tells us, jurisdiction was exercised between the two rivers, but he does not tell us it was exercised over all the territory between them … 6 That our Congress, understood the boundary of Texas to extend beyond the Nueces-- … the Congress of the United States, understood the state of Texas they admitted into the union, to extend beyond the Nueces-- Well, I suppose they did-- I certainly so understand it-- But how far beyond” (Lincoln, Speech to Congress)? Lincoln took each and every one of Polk’s original arguments for war, and evaluated them for accurateness and justifiable thinking. The president declared war based on unrelated, unclear and illegitimate evidence. After going through them all, it is very clear that Lincoln believed that the war was both unnecessary and unprovoked.

After the brutal fight in the capital, Mexico City, a resolution was found. On Feb. 2, 1848, the Treaty of Guadalupe Hidalgo was signed. This treaty was responsible for establishing the Rio Grande, not the Nueces River, as the border separating the United States from Mexico. Also under this treaty, Mexico released all claims to Texas, and now recognized the annexation of Texas. Mexico also agreed to sell more than 500,000 miles of land, including California, New Mexico, and the rest of its territory north of the Rio Grande, for $15 million. Additionally, the United States assumed $3.25 million in claims that the American citizens previously had against Mexico.

Looking at the Mexican War, the basis of all of the causes can be traced back to the idea of manifest destiny. The word coined by James O’Sullivan quickly swept the nation. The United States believed God gave them a superiority that allowed them to expand their lands in all directions, and his word now gave them a justification to do so. President Polk, who was ultimately responsible for the Mexican War, agreed with this concept so much, that he spoke about it in his inaugural address. He believed that the annexation of Texas was justified. The conflict borders that along with it only aggravated Mexico more, but he believed that Texas held the border that gave him more land. He wanted to “reoccupy” Oregon, as a way of countering Texas, a slave state, with a new free state. He also wanted Mexico’s northern territories of California and New Mexico. It was driven by manifest destiny, but backed by Mexico’s lack of control within them. Because Polk was so blinded by manifest destiny, he presented arguments to Congress, as justification for war, that were irrelevant and without proper evidence and justification. Lincoln was able to see through that, and made it clear when he presented this information in a speech to Congress. Through all of the issues and controversies, the United States came out victorious. Through the Treaty of Guadalupe Hidalgo, Mexico relinquished its right to Texas, accepted the annexation of Texas, agreed on the border of the Rio Grande, allowed the United States to purchase the Northern territories for $15 million and agreed that the United States would assume $3.25 million in claims. By looking at all the causes, results and controversies associated with the Mexican War, everything can be traced back to James O’Sullivan’s idea of manifest destiny.