Understanding the concept of manifest destiny is essential to understanding the Mexican War in its entirety. John L. O’Sullivan was the first to coin the term “Manifest Destiny” in 1845. This term was used to justify white settlers acquiring the land they wanted (370). He “called them to resist all foreign powers – British French, Mexican or Mexican that attempted thwart ‘the fulfilment of our manifest destiny, to overspread a continent allotted in the Providence for free development by our yearly multiplying billions (370). This new term was quickly adopted in the United States. They were able to justify acquiring new territories and land west of the Mississippi. This was due to the Americans believing that this was a God-given right, based on their superiority and white culture (370).
The Mexican War was ultimately triggered by this notion of Manifest Destiny. The Americans wanted more territory in the west. Texas, which was just independent from Mexico, was a fascinating prospect. It was however, unsettling for the North, that another slave country would be added. To please the Northerners, Democrats suggested expansion into Oregon as a state that would be free. This would mirror Texas’ status as a slave state. “The United States decided in 1818 that Oregon would be ‘jointly occupied’ and leave it ‘free and available’ for settlement by either country” (371). However, politicians were calling now for a “reoccupation” (378). This presented a threat for Britain, possibly causing another conflict, but it was decided by manifest destiny. Polk made a new offer to Britain which was passed by the Senate. This gave the country the land peacefully. There was also a dispute over the border borders. The border between Mexico and Texas was The Nueces River according to the Mexicans. Texas, however, claimed it was along The Rio Grande. Mexico was frustrated by the movement and placement of an army at these borders. Polk was also drawn to New Mexico and California by the force of destiny. Polk had originally planned to buy these territory but decided that it would take a military force to secure them. This only fueled the already heated fire. This only added fuel to the already aggravated fire. “Foreign power should consider the annexation Texas of the United States, not as the conquest and expansion of her dominions by violence and arms but as the peaceful acquisition and confederation of territory once hers. This will diminish the possibility of war, and give them new and expanding markets for products” (Polk. Inaugural address).
Polk was so driven and enthralled by the idea that destiny would manifest, he wanted to claim Mexico’s remaining northern states, California and New Mexico. This added tension and frustration between Mexico and America. He initially wanted to buy the Mexican territories, but they refused to sell him. He was acutely aware of all the chaos going on, which gave him hope. “Comanches, Kiowas and Apaches had attacked Mexican towns and ranches since the 1830’s, killing thousands of people” (378). Polk and his administration knew this and concluded that Mexico couldn’t control its northern territories. According to them, this meant Mexico would lose control of its northern territories. These facts, combined with Polk’s desire to manifest his destiny, led him to conclude that military force was required to secure the territories he wanted.
The Mexican War began with the annexed Texas. In his inaugural address, Polk stated “…The Republic of Texas expressed her desire to be a member of the Union. “Polk, Inaugural Speech” Mexico warned that the annexation Texas would be considered a war crime regardless of this fact. “Annexing Texas was a risky move that could lead to war. Mexico has never given up its claim to its former providence.” (377). The
In addition to the problems caused by Texas’ annexation, there were also disputes between Mexico and the United States over its borders. “The Rio del Norte was the Republic’s border, as declared by Congress of Texas on 19 December 1836. Its jurisdiction was extended beyond the Nueces. The country that lies between the Del Norte River and the Congress was represented. This had also been included in the convention of Texas. The Rio Grande was considered the border’s southernmost point by the United States and the Republic of Texas. Mexico, however, thought that the Nueces River was the border. “Polk had already given General Zachary Taylor the order to move his 4,000-man armies 150 miles south of its Nueces River position” (378). Mexico considered this an act for aggression. Mexico responded by ordering the Matamoros Mexican General to withdraw to the Nueces. The Mexicans refused to comply and attacked on April 25, 1846. The Mexicans then captured 16n of their captives and killed 16n more.
Polk claimed that the Mexicans started the Mexican War, which he later justified. His original intentions were peaceful. The commanding general ordered the troop movement to the Del Norte to be peaceful and abstain from any aggressive acts against Mexico or Mexican citizens. (Polk, War message) Polk’s War Message to Congress states that the above-mentioned troop movement was peaceful. He was not planning to act aggressively towards the Mexican citizens or army. The Mexican army didn’t see the movement as peaceful and killed 16 people and captured the rest. After that, Polk declared war. “Mexico invaded American soil and has passed the United States’ boundary,” (378). “As war exists, even though we have tried to avoid it, it exists because of the act by Mexico itself. Therefore, we are obligated by every consideration of duty, patriotism and honor to declare the country’s rights …”. Polk’s cabinet had approved a war communication before the news reached Washington. This has caused a lot of controversy (378). Polk declared war even though he had been given permission to do so by his cabinet. Polk was merely using Mexico’s retaliation to justify declaring war.
Abraham Lincoln, an Illinois Whig representative, addressed Congress at that time about the issues he found in Polk’s argumentation and justification for war. “Before Abraham Lincoln took the seat, he had challenged Polk’s intelligence and honesty” (379). He then decodes each of the president’s arguments and explains why they don’t have any backing. He then goes on to explain the president’s arguments for war and why they are weak or lacking support. … 2 That Texas claimed the Rio Grande as her Western boundary….But that is false. Texas claimed it in various ways…. Now, if she claims it in writing, he tells us that Texas and the U.S. had previously recognized the Rio Grande as her border…. He also says that Texas’s boundary was extended beyond the Nueces…. The Congress of the United States understood Texas as a state they accepted into the union. But, how far beyond? Lincoln analyzed each Polk’s original arguments and assessed their validity and justifiable thinking. Unrelated, unclear and illegitimate data was what the president used to declare war. After looking through all the evidence, it becomes clear that Lincoln believed war was unprovoked and unnecessary.
After the violence in Mexico City’s capital, there was a solution. The Treaty of Guadalupe Hidalgo signed February 2, 1848. This treaty established the Rio Grande as the border between the United States and Mexico. Mexico was also free to give up all claims to Texas under the treaty and is now recognizing Texas’ annexation. Mexico also agreed $15 million to sell Mexico over 500,000 miles land, including California, New Mexico, Texas, and the rest north of Rio Grande. The United States also took on $3.25million worth of claims previously filed against Mexico by American citizens.
The Mexican War is a case study in manifest destiny. James O’Sullivan’s invention quickly spread across the country. The United States believed God had given them the ability to expand their lands all around the world. His word gave them justification. Polk, the man who led the Mexican War, was so in agreement with this idea that he gave his inaugural speech. He believed that Texas’ annexation was right. Mexico’s conflict borders only made matters worse, but he believed Texas was the one that provided him with more land. As a counter to Texas, a slave-state, he wanted Oregon “reoccupied” and a new state. He also desired Mexico’s northern territories in California and New Mexico. The manifest destiny of Mexico was the driving force behind it, but Mexico’s lack thereof in controlling them supported it. Polk was so blinded from manifest destiny that his arguments for justification of war were not valid and without sufficient evidence. Lincoln saw through all of this and presented it to Congress in a speech. The United States won despite all the controversies and issues. Mexico gave up its right of Texas in the Treaty of Guadalupe Hidalgo. The United States accepted Texas’ annexation and agreed to buy the Northern territories from the United States for $15 million. In return, the United States also agreed to $3.25million in claims. The Mexican War’s causes, effects, and controversies can all be traced back towards James O’Sullivan’s manifest destiny idea.
