The U.S. wanted Texas, and the Mexicans demurred. Texas had gained its independence from Mexico in 1836. There were some territorial issues and President Polk ordered General Zachary Taylor and his army into Texas. The Treaty of Guadalupe Hidalgo laid down the Rio Grande boundary. The U.S. got New Mexico and California, and shelled out $15 mil to Mexico.

from James K. Polk's Inaugural Address, March 4, 1845:

None can fail to see the danger to our safety and future peace if Texas remains an independent state or becomes an ally or dependency of some foreign nation more powerful than herself. Is there one among our citizens who would not prefer perpetual peace with Texas to occasional wars, which so often occur between bordering independent nations? Is there one who would not prefer free intercourse with her to high duties on all our products and manufactures which enter her ports or cross her frontiers? Is there one who would not prefer an unrestricted communication with her citizens to the frontier obstructions which must occur if she remains out of the Union? Whatever is good or evil in the local institutions of Texas will remain her own whether annexed to the United States or not. None of the present States will be responsible for them any more than they are for the local institutions of each other. They have confederated together for certain specified objects. Upon the same principle that they would refuse to form a perpetual union with Texas because of her local institutions our forefathers would have been prevented from forming our present Union. Perceiving no valid objection to the measure and many reasons for its adoption vitally affecting the peace, the safety, and the prosperity of both countries, I shall on the broad principle which formed the basis and produced the adoption of our Constitution, and not in any narrow spirit of sectional policy, endeavor by all constitutional, honorable, and appropriate means to consummate the expressed will of the people and Government of the United States by the reannexation of Texas to our Union at the earliest practicable period.

The Annexation of Texas
In January 1844, Texas and the United States signed a annexation treaty that would allow Texas to become a state of the U.S. This treaty, however, was rejected by the senate on the basis that Texas was a slave state. However, in the election of that year, the citizens of the United States clearly showed their wishes to have Texas as a state and sole control of Oregon territory.

Almost a year and 1/2 later on March 1, 1845, Congress passed a joint resolution to annex of Texas, however, this treaty left the United States with less advantage than the one in 1844. Three days before he retired from office, President Tyler signed the annexation and on December 29, 1845, Texas was formally admitted as the twenty-eighth state, one of fifteen having slavery.

Mexico, however, never respected Texas' independence and felt the annexation an insult to their nation. Many citizens felt the need to go to war with the United States. However, due to internal conflicts, this was not a very good idea. But it was not helped by the army coup in December 1846 of General Jose Joaquin de Herrera. He was replaced by Mariano Padres.

In November 1846, President James Polk sent John Slidell to meet with President Herrera with the intent of attempting to buy the land that was ceded to the United States following the Treaty of Guadalupe Hidalgo. He returned in March of the following year...without ever meeting either presidents.

During Slidell's stay in Mexico, things between the 2 nations had become rather tense, to say the least. Still bitter over the the annexation of Texas, arguments developed over the boundary of Texas with te U.S. and Mexico so President Polk sent General Zachary Taylor to the Rio Grande.

On April 25, 1846 Mexican troops attacked the U.S troops stationed there in a small but history altering skirmish. And shortly there after on May 13, Congress declared war on Mexico.

Despite the larger size of the Mexican army, it was woefully backwards in many respects compared to the United States which would cost them dearly by the end of the war 2 years later. The American strategy was a 3 pronged attack the intent of seizing control of northern Mexico to force an early peace.

Two American armies moved south from Texas, while a third force under Colonel Kearny travelled west to Santa Fe, New Mexico and then to California. In a series of battles at Palo Alto and Resaca de Palma, the army of General Zachary Taylor defeated the Mexican forces and began to move south after inflicting severe casualtes on the Mexicans.

Interestingly, soon after the declaration of war white pionners in California began a revolt and formed the Bear Flag Republic with its capital in Sonoma. It last scarcely a month before the arrival of the American Commodore John Sloat who took Monterey without a fight (The city barely had any powder) while Colonel Stephen K. Kearney marched towards the soon-to-be state and scarcely 1/2 a month since Congress declared war, Alta California governor Pío Píco capitulated to the Americans on January 13, 1847 (For more info on the battles in the Los Angeles area, see Battles for Los Angeles).

Meanwhile, by September, the forces of Zachery Taylor attacked the city of Monterrey in a bloody three-day battle with Mexican troops under the command of General Ampudia. Following the capture of the city by the Americans, a temporary truce was reached to allow both sides to rest.

However, during the short truce, former Mexican president, Santa Anna had returned from exile, and raised a 20,000 man strong army to take on the Americans. As the war dragged on, with the Mexicans losing land and the major battles, they still refused to sue for peace. President Polk soon realized that only a complete victory over the Mexicans would end the war.

To achive this goal, General Winfield Scott proposed what would become the largest amphibious landing in history, (at that time), to seize Mexico City. Executed on March 9, 1847 with the landing of 12,000 men under Scott's command at the port city of Veracruz. The expedition took 6 months and several bloody battles including the Battle of Cerro Gordo (April 18), Contreras (August 20), Churubusco (August 20), Molino del Rey (September 8) and Chapultepec (September 13), before the Americans finally enter the capital on September 14.

From then until the signing of the Treaty of Guadalupe Hidalgo on February 2, 1848. Santa Anna continued to harrass the Americans in a futile attempt to save Mexico from surrendering. It finally ended by his government asking for his military resignation (He had resigned the presidency earlier).

Causes of the War
The Mexican-American War was the first war that United States fought that resulted from the idea of a Manifest Destiny. It was part of the massive era of expansionism sparked by Andrew Jackson. It did however, complete the Manifest Destiny's idea of a nation from "sea to shining sea" at least. This is not to say that Mexico wasn't exactly against going to war, they were very bitter of the independence of Texas, and even more so by the United States' annexation of it. Both wanted war to some extent, and they got it.


Was the Expansion of Slavery the Root Cause of the Mexican-American War and the Decision to Annex Texas?

During the annexation of Texas and the Mexican-American War, the so-called "conscience" Whigs, opposed to the United States' involved in these actions, attacked them as attempts to expand slavery. After all, the land gained with the annexation of Texas and gained from Mexico due to the war would almost certainly be open to slavery. However, other reasons, not the least of which were the doctrine of Manifest Destiny and the desire to gain an entrance into the Pacific, were more important factors in Presidents John Tyler's and James K. Polk's decisions to annex Texas and go to war with Mexico.

During the times of the Tyler and Polk Administrations, slavery was creeping up as a central issue in American national politics. The Northern free states were intent on keeping slavery from expanding further while the slave-owning South was focused on protecting its "right" to own slaves through power exercised in the Congress. However, since Henry Clay's famed Missouri Compromise of 1820, a precarious balance existed between North and South; each consisted of the same number of states and therefore controlled the same number of Senate seats. The annexation of Texas and the land gained from Mexico (the Mexican Cession) in the war threatened to tip the scales in favor of the slave states. Even more damning was the fact that both presidents were Southern Democrats at heart, with much to gain by pleasing their Southern power-base.

Of much greater importance to the United States government in gaining these territories, however, was the spreading of American democratic ideals. According to the precepts of Manifest Destiny, the United States had a "God-given duty" to enlighten the "savages" it shared the continent with by bringing democracy to them. Mexico, populated by Hispanic Catholics, was therefore seen as inferior by the WASPish American populace.

The use of Manifest Destiny as a justification for expansions is further proven by President Polk's and Secretary of State Daniel Webster's handling of border disputes with Great Britain over Maine and Oregon. Instead of going to war against Britain as the United States did with Mexico over border disputes with Texas and sparking a violent conflict, the United States settled both of these controversies peaceably. Polk and Webster both compromised in order to preserve the peace: Polk ceded to Britain some of Oregon Country in the Oregon Treaty of 1946 and Webster signed the dispute-settling Webster Ashburton Treaty, allowing the United Kingdom control over half of a disputed section of Maine. In both of these instances, America did not go to war with a nation that held similar "enlightened" ideals, institutions and a WASPish population over border disputes as serious as the one with the "inferior" Mexico.

On the other hand, it can be argued that the United States went to war with Mexico, rather than Britain, for other reasons. Mexico was a much weaker opponent than the current world power. Despite this seemingly sound logic, America had defeated Britain in the Revolutionary War and fought it to a stalemate in the War of 1812. The supremely arrogant James K. Polk would not hesitate over standing toe-to-toe with a foe that the United States had, in his view at least, defeated in the past.

The reasons that the two presidents gave for their expansionist policies also show that slavery was not foremost on their minds. Tyler simply grabbed at an opportunity by annexing the independent Republic of Texas. He wanted to prevent Europe from gaining a dominating influence on the fledgling nation and using its land to produce cotton to offset the tariffs imposed on its cotton. Furthermore, Polk only went to war with Mexico in order to gain California. He saw California as America's vital entry into the Pacific and would use any means necessary, even war, to secure such a vital treasure. The Mexican-American War was fought to gain important ports, not future slave states.

Texas was not annexed nor was the Mexican-American War fought solely to spread the "peculiar institution" of slavery. Though both Presidents Polk and Tyler had much to gain in pleasing their Southern, slave-owning power-base by admitting more slave states into the Union, slavery was not foremost on their minds. Of far greater importance to the two men were the spreading of the democratic institutions of America, preventing Europe from gaining influence in the Americas in defiance of the Monroe Doctrine, and gaining an access into the Pacific Ocean.


This essay is a product of Node Your Homework.

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