What Was The Cause Of The Mexican American War

Jacob Mehlman
11-23-14
U.S. History
The Cause of the Mexican-American War
The Mexican-American war was a very controversial war in U.S. history. Many people say that the U.S. provoked Mexico by stationing troops on the Rio Grande River while the two countries were negotiating boundary issues. Others conclude that the coveted land at stake was the true cause for war. This conclusion is clearly supported by the main outcome of the war, which was the seizure of almost half of Mexico’s land. This captured land now makes up the states of New Mexico, Arizona, Texas, and California. Also, the expansionist values of the James Polk administration also could easily help justify this conclusion. Therefore, the U.S. started the Mexican-American War because
James Polk acted on the ideals of expansionism, which the country then justified by using the language of manifest destiny.
To begin, the ideal of expansionism explains why the United States would want to engage in war with Mexico. The president at that time, James Polk, was definitely interested in expanding America’s territories. Often times, the Mexican American war was referred to as “Mr. Polk’s War”. His expansionist values were carried out successfully because of the victory of this war:
In a mere four years, the expansionist movement—led by the Democratic administration of James K. Polk (1795–1849)—achieved its goal of making the United States a continental power. American territory approximately doubled as a result of Texas annexation (1845), the settlement of the Oregon boundary dispute with Britain (1846), and the Mexican cessation (1848) (Scholnick 710).
In terms of adding land to the U.S., the James Polk administration was a machine that did not seem to stop. Not only does Polk’s administration add the Mexican cessation and Texas to the U.S. from the Mexican-American war, but it also gains territory along the border of Canada where Oregon is. The negotiations between the British and the United States could have potentially started yet another war, but luckily for Polk they agreed to split the land at the forty-ninth parallel. This expansionist drive did not end with Polk, however, but rather continued on and shaped the United States of today: “The continental United States as it exists today came into being. That expansionist drive, however, was not dead: Alaska was purchased in 1867. Following the war with Spain in 1898, the United States came to control Cuba, Hawaii, Puerto Rico, and the Philippines, becoming a global power” (Scholnick 710). The reality of U.S. expansion is that it did not stop until 1959, when Alaska and Hawaii were added. This illustrates that expansionism has always been an American value, for better or worse. The hunger for land was almost insatiable, and the people of the 1840s wanted to expand. James Polk’s actions were clearly in line with many Americans’ wishes to expand westward:
Although both individualism and the pioneer spirit had prevailed from the beginning, it was not until the ‘forties [1840s] that the enterprise of the pioneer seemed the most perfect expression of American individualism…the fact that the pioneer movement now became involved with territorial issues of national concern; and above all, perhaps, the general land hunger which caused the pioneer to seem now not a deviation from but the very expression of Americanism. It was in the fervent appreciation of the pioneer movement that there were forged all the links uniting individualism and expansionism (Weinberg 57).
The ideals of manifest destiny and expansionism ran deep in American culture. Americans everywhere wanted to actively expand the borders of the U.S. because they wanted their own cut of America, a land made for the people. They also thought that by expanding the U.S., they were also expanding the core values of America, including freedom. In their eyes, moving Indians and Mexicans out of their way was only a small price to pay for spreading America.
Additionally, James Polk sent troops to Mexico because the Mexican government wouldn’t comply with the offer that was made. This offer was not a favorable one for Mexico, and really only benefited the U.S.’s expansionist goals. The particulars of the negotiations between Mexico and the U.S. tell the true story of how the war was started. James Polk sent James Slidell, a Louisiana politician and close ally, to negotiate with Mexico:
Slidell’s connections landed him the official task of negotiating a deal with Mexico. He was instructed to offer a settlement of all U.S. claims against Mexico, in exchange for recognition of the Rio Grande as the boundary between the two nations. In addition, Polk instructed Slidell to try and buy California for $25 million. The Mexicans rejected Slidell and his mission outright. He responded to President Polk by hinting that the Mexican reluctance to negotiate might require a show of military force by the United States (PBS 1).
The way that Slidell negotiated is questionable for a few reasons. First, offering to buy a valuable piece of land and getting turned down should not have been a surprise to Polk or Slidell, but they obviously would not take “no” for an answer. It also seems inappropriate to try and buy more land off a country while still negotiating over another piece of land that was once theirs. When Slidell told the president that military power would be needed, it created the opportunity that Polk had been waiting for. Polk could finally justify to the American people, and more importantly Congress, a need for war with Mexico:
The strong desire to establish peace with Mexico on liberal and honorable terms, and the readiness of this Government to regulate and adjust our boundary and other causes of difference with that power on such fair and equitable principles as would lead to permanent relations of the most friendly nature, induced me in September last to seek the reopening of diplomatic relations between the two countries…Not only was the offer rejected, but the indignity of its rejection was enhanced by the manifest breach of faith in refusing to admit the envoy who came because they had bound themselves to receive him…the Mexican Government refused all negotiation, and have made no proposition of any kind.
In my message at the commencement of the present session I informed you that upon the earnest appeal both of the Congress and convention of Texas I had ordered an efficient military force to take a position "between the Nueces and the Del Norte." This had become necessary to meet a threatened invasion of Texas by the Mexican forces, for which extensive military preparations had been made. (Polk
2).
This justification to the American people was directly made possible by Slidell. Had Slidell not told the president to send American forces to the Rio Grande, then perhaps they would not have been attacked by the Mexicans, which was the final push needed in order to start the war. Polk’s call to war was met with ample evidence that the Mexicans needed to be fought, and then war was passed through Congress. Lastly, the United States used the values of manifest destiny to justify their controversial expansionist actions. Expansionism came at the cost of making many people leave from their native lands. The way that Americans decided to justify kicking people out of their land was through the concept of manifest destiny. Manifest destiny was the idea that Americans were God’s chosen people, and it was God’s will that they would settle the land they were on. It also gave them the idea that Americans were a superior race of people and were going to use the world better than others. Fighting the Mexican-American war was explained through manifest destiny:
The war between the United States and Mexico broke out in May 1846.
Though the causes of this conflict were many, the most important was the spirit of expansionism called manifest destiny. Thousands of Anglo-Americans believed that it was God's will that they should move west across the entire North American continent, occupying lands of Mexicans and Indians and casting their inhabitants aside in the process. For many, manifest destiny had an economic dimension, justifying a more efficient use of natural resources by the industrious Anglo-Americans. Mixed in with this economic motive was an attitude of racial superiority. As one American writer wrote, ‘The Mexicans are Aboriginal Indians, and they must share the destiny of their race’ (Griswold del Castillo
77).
Many Americans used manifest destiny to rationalize their own individual endeavors of settling west, and their feelings were also upheld in U.S. government. The government certainly used manifest destiny to vindicate fighting the Mexican-American war, along with many other ventures that had land at stake. If anything, manifest destiny could surely be described as American propaganda. The concept itself had little factual truth to support its claim of racial superiority. This ideal, nevertheless, was spread through American culture by people like John Frost, who is often referred to as the unofficial historian of the Mexican American war: “Frost’s popular history of the war legitimated the doctrine of Manifest Destiny that designated the United States as God’s favored nation and that characterized the inhabitants of its territory as God’s chosen people” (Pease 732). Through popular culture, manifest destiny became synonymous with expansion, and was a generally accepted idea among the American people. Part of the reason why there was not a large opposition to the Mexican-American war was because so many people believed in manifest destiny. The people who disagreed with the war were far fewer in number than those who supported it, and this allowed for the questionable war to take its course.
To recapitulate, the U.S. started the Mexican-American War because James Polk acted on the ideals of expansionism, which the country then justified by using the language of manifest destiny. Though many Americans at that time fully believed in expansionism and manifest destiny, there were those who opposed those views. They saw the horrible repercussions of expansionism, and they saw the flawed logic that manifest destiny was built on. Many of them wrote about their views, such as Frederick Douglass:
Frederick Douglass (1818–1895) observed on 21 January, 1848 that ‘Mexico seems a doomed victim to Anglo-Saxon cupidity and love of dominion. The determination of our slaveholding President to prosecute the war, and the probability of his success in wringing from the people men and money to carry it on, is made evident, rather than doubtful, by the puny opposition arrayed against him. No politician of any considerable distinction or eminence, seems willing to hazard his popularity, or stem the fierce current of executive influence, by an open and unqualified disapprobation of the war’ (Scholnik 713).
A point that Frederick Douglass wants to make is that Americans often chose to be ignorant of all the terrible consequences for Mexicans and Indians had to suffer through because of their expansion. While the U.S. won the war, the Mexicans took a hard loss and gave up almost half their territory. President James Polk knew he wanted that land when he entered office, and the war was made for that purpose of obtaining it. Frederick Douglass’s view represents the small group of those who saw the dark truth behind the Mexican-American war.