Mexican-American war started by the Texas annexation by the Union. Texans, who were mostly Americans, declared themselves independent in March 2, 1836 as the Republic of Texas. But they didn’t want to stand alone thus they asked to join the Union. Mexico never accepted the Republic of Texas. Thus, the areas Texas claimed, all land in the north of Rio Grande, emerged border dispute between America and Mexico. President of United States at that time, James K. Polk, sent his army to defend Texas from Mexico invasion and suddenly conflict happened. Thus, Congress declared war in summer 1846. This war takes one and a half year. Ended by the Treaty of Guadalupe Hidalgo signed in February 2, 1848, US gained their territories stretched from coast to coast and completed their mission of Manifest Destiny.
United States expansion cannot be separated from American vision of Manifest Destiny. They believed that it was their fate to conquer the land of America. This thought came from the early American settlers who were the Puritans. Puritanism teachings said that the earth was given for human to be explored and used for man welfare since they are the chosen people of God. They looked America as the Promised Land in which they have absolute authority for it. Consequently, they underestimated the non-Americans. Even Calvinists saw them as trials from the devil that they should survive from: “In Puritans initial zeal to establish the Kingdom of God in America, they had regarded the non-Americans, and even nature itself, as obstacles thrown in their way by the devil.” (Horton, 43). They saw these people as backward peoples and that they had right to spread their cultures on them in order to civilized them. O’Sullivan said that “Our Manifest Destiny to overspread the continent allotted by Providence for the free development of our yearly multiplying millions.” Sullivan argued that American had a God given right to bring the benefits of American democracy to others. (Out of Many, 240). Thus, they justified the termination of non-American, in this case Mexicans, both of their lives and their cultures. The very first attempt to realize this American Manifest Destiny did by the government was encouraging Americans settlers to move westward, towards Mexican territories. Federal government played the major part; they sent military-qualified expeditors such as Lieutenant Zebulon Pike to examine the terrains, resources and conditions of the west. Then, the government released the pictures, maps and illustrations to gain people’s interest. It can be seen that the government was seriously promoting people to go west because later in 1825 there was also a federal protection for the moving settlers of Santa Fe Trail. There were some reasons why American settlers willing to move west; 1. The United States was experiencing a periodic high birth rate and increases in population due to immigration. And because agriculture provided the primary economic structure, large families to work the farms were considered an asset. The U.S. population grew from more than five million in 1800 to more than 23 million by mid-century. Thus, there was a need to expand into new territories to accommodate this rapid growth. It was estimated that nearly 4,000,000 Americans moved to western territories between 1820 and 1850.
2. Frontier land was inexpensive or, in some cases, free. It opened opportunities and associated with wealth. (http://www.pbs.org/kera/usmexicanwar/prelude/md_introduction.html) Thus, so many Americans settled in western areas that were belonged to Spanish (later, Mexico). They were clearly interlopers. But these Americans were so stubborn that they would not assimilate nor adopt Mexican way. They believed that it was the way to spread out American democracy in the society. But living that way in such number can be also considered as destroying Mexican cultures. It clearly seen by the way Texans disliked Mexican authorities and revolted to gain their own independence leading to the Texas annexation that rise conflicts between two countries. Thus, Americans second attempt to realize its Manifest Destiny mission was by war. Having many settlers all over the territories supported them in gaining this. For example, by 1830 there were more than 20.000 Americans lived in Texas and they were opposing Mexicans government. “These settlers did not intend to become Mexican citizens. Instead, they planned to take over Texas.” (Out of Many, 245) Thus, it leaded to the war. Although Mexican-American war gained so many pros and contras, but it was clear that the government at that time did whatever it takes to complete their Manifest Destiny. It was the president James K.Polk from Democratic Party who was an expansionist. He was optimistic to make America stretched from the east until west coast. So, he sent his secret envoy, John Slidell to offer Mexico some money in order to buy their lands but Slidell was rejected. Angry Polk sent his army to the disputed zone making his soldiers involved in skirmish with Mexican soldiers. He lied that Mexico started it first and asked congress for war; “War exist, and, notwithstanding all our efforts to avoid it, exists by the act of Mexico herself. This claim of President Polk’s was of course contrary to fact.” (Out of Many, 247) It was clear that he wanted to expand America, although by war, because the beginning of the war was confusing, no one knows what the reality happened at the border that raised the war. Even Abraham Lincoln questioned Polk’s account of the border incident. (Out of Many, 247) but still, America could not resist this Mexican-American war.
The Treaty of Guadalupe Hidalgo brought America new and larger territories; Mexican ceded its northern provinces of California and New Mexico (including present-day Utah, Arizona, Nevada and part of Colorado) by means, completed their Manifest Destiny, conquering all lands from Atlantic Ocean to Pacific Ocean-from coast to coast. But still, there were positive and negative impacts of this. The most significant effect of having these new territories was economic growth in America. Not only larger lands that were considered as wealth but also the natural resources it gave. Lands and new territories might give Americans higher expectation to improve their life and find their own opportunities that lead both of the settlers and the nations’ economic welfare. But the findings of gold in California benefited a lot in the economical improvement of America. And also, the settlement and the life of its people improved significantly as clearly seen in the nearest town, San Francisco. But apparently, there was also negative effect of gaining those new territories; there was a crash in the body of politics. There was controversy of the legalization of slavery to the new territories between the Democratic and Whigs Parties where the northern Democrats and Whigs opposed the extension of slavery while southern Democrats and Whigs supported. Ironically, it was the roots of the separation, cracked the nation into two; Union and Confederacy, and lead them to the Civil War.
History shows clearly that whenever Americans want something another nation has such as land and resources, they are able to justify themselves to take it using their theology; “The usual contrivance is the age-old theory that non-white peoples are unable to govern themselves, so we must heed our Divine Mission to liberate them from their own ignorance and corruption, bringing our gifts of freedom, democracy and Christianity—whether they want it or not.” (Fitzgerald, Michael). All those theories presented by Americans probably just a mask to justify their greed of wealth. Thus, Mexican-American war was just a political move to gain larger territories and Manifest Destiny was nothing more than “a cluster of flimsy rationalizations for naked greed.” (George Tindal, in Michael Fitzgerald’s article)
Out of Many: history of the American people, John Mack Faragher. American literary thought, Ron W Horton.
(http://www.pbs.org/kera/usmexicanwar/prelude/md_introduction.html) Manifest Destiny: American Imperial Myth, Then & Now, Michael Fitzgerald. (article)