The Mexican-American War had several causes, some
of which major and others of which minor. The most important, however, were the
crisis, westward American movement, the ideal of Manifest Destiny, and the actions carried out by the President Tyler and
The first cause of the Mexican-American War was Texas
and California. When Texas
broke away from Mexico in 1836, Mexico
did not recognize it as an independent republic but as a corrupted territory.
This territory, they believed, was nonetheless still a part of Mexico. The government of the United States
believed differently, however. As his time in office was coming to an end, President
John Tyler received enough support to annex Texas. Mexico was enraged as Texas
entered the Union as the 28th state and believed that the annexation of Texas
was a call for the necessity of war (“Mexican-American War”).
Furthermore, when President James Polk had John Slidell travel to Mexico
offering a sum of 30 million dollars for New Mexico and California,
Mexico grew angrier for they would gain nothing from the loss
of Mexico if they were to complete the sale. Mexican officials never met with Slidell, however, for they
refused to accept him (“Mexican-American War,” 1). Then on January
13, 1846, General Zachary Taylor and his troops were ordered to travel down to the Rio Grande to maintain the disputed border
of Texas (Mexicans believed that the Texas border was the Nueces River while Texans and the U.S. believed it to be the Rio
Grande)(“Countdown to the War,” 1). Mexico,
thinking that Taylor and his men were on its land, attacked the American unit in an act of self defense (Heys, 1). Soon after these events, the United States
declared war on Mexico on May
13, 1846 (“Mexican-American War,” 1).
Another cause of the Mexican-American War was the westward movement of citizens of the United
States. At this date and time Americans were
constantly looking for land to start farms or sell to incoming farmers. They
found the most easily accessible and available land in Texas. There was also the ideal that the Southerners traveled into Texas
in order to get another slave state into the Union and relinquish Southern power (Heys, 1). Nonetheless, as waves of people from the U.S.
poured into Texas, they began to undermine the authority of the Texans and the
Mexican government. As if this were not enough, the invaders disobeyed Mexican
laws and regulations such as the antislavery laws. These behaviors combined greatly
contributed to the disproval of U.S. citizens by Mexican officials/law
makers (“Mexican-American War,” 1).
Next, there was the ideal of Manifest Destiny, which is the American ideal that the United
States should stretch from ocean to ocean as one massive nation. This ideal greatly contributed to the westward migration of Americans as they traveled across the continent
in search of economic gain (Heys, 1). The greatest example of expansion for economic
gain was seen in the United States’ desire to acquire
California in an effort to establish markets and an economic base in heavily
populated Asia (“Mexican-American War”).
Lastly, there were the motions of the presidents who were in
office at the time when Mexican and American tensions were rising. First, there
was President Tyler. In an effort to gain support from voters for the upcoming
election, Tyler supported the annexation of Texas. In fact, Tyler was the one that got the
joint resolution to annex Texas passed, which was the main reason for Mexican
hostility. Then, there was President Polk.
After running on a platform centered on expansionism, Polk put his ideals to work encouraging western expansion and
the ideal of Manifest Destiny. After Mexico
refused to negotiate Slidell and attacked U.S.
troops along the Rio Grande, Polk asked Congress to declare war on Mexico,
once and for all starting the war (Heys, 1).
In conclusion the causes of the Mexican American War were actually
quite clear and simple. First, there was the Texas
crisis and the argument over land. Then, there was the never halting westward
advance of citizens onto Mexican territory. Finally, there was the ideal of Manifest
Destiny, which almost all U.S. citizens believed in at the
time. When all of these occurrences were combined, enough had been done to spark
a war; a war of which was important to U.S. land expansion.
“Countdown to War.” A Coneise History of the U.S.-Mexican
War. August 8, 2004. Internet. Online. Available <http://www.dmwv.org/mexwar/history/count.htm>
Heys, John. “Enough Blame to Go Around: Causes of the Mexican-American
War.” 1995. Internet. Online.
“Mexican-American War.” May 30, 2006. Internet. Online. Available <http://en.wikipedia.org/wiki/Mexican_War>
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