The United States in 1846 was not justified in going to war with Mexico. The United States did not have proper justification to respond with violence against the Mexican government. The war with Mexico was also a product of the United States’ belief of manifest destiny. Polk’s over ambition to seize new territory from the Mexicans and disappointment over their refusal to sell him California also possibly played a factor in his willingness to wage war against Mexico. The United States under the leadership of president Polk clearly provoked Mexico into attacking US troops. All these reasons show that the US had no business starting a war with Mexico for territory that was rightfully theirs.
The war with Mexico came at a time when much of the country had strong feelings of manifest destiny. Manifest destiny is the belief that fate had preordained the US to expand from the Atlantic to the Pacific oceans and from Canada to the Rio Grande river. This idea which was coined by John O’ Sullivan was very popular in the 1840′s. This ideal had strong influence and was one reason that their was so much popular support for the US expansion west. This ideal while nationalistic did not give us the right to go into Mexico and seize land which was rightfully theirs in the first place. They had the right to expel any US citizens that were living on their country’s land especially if they where not abiding by their laws. This alone makes even the annexation of Texas not completely just. The US vision of manifest destiny helped to win the public’s support for the Mexican war. Yet the public was misled by this sense of manifest destiny and those that did support it supported an unjust war.
President Polk during his presidency lusted for more land than the country had ever before controlled. Not only did he capture Texas but also California and Oregon. While attempting to gain California through peaceful means he sent John Slidell to Mexico City to offer the Mexicans up to $25million dollars for California yet this offer was rejected by the Mexicans as insulting. This led Polk to frustration and his willingness to try backhanded and sneaky new ways to get the Mexicans to give him the territories that he desired. This showed that Polk was consumed with greed for new territory. He no longer cared how he claimed his no territory. Polk was consumed with a need to make his campaign promises a reality and to make the prophecy of manifest destiny a reality. His greed for land is evident in his behind the back tactics that he attempted to employ against the Mexicans. He also was seeking a form of revenge for the deaths at the Alamo and the refusal of his proposal to buy California from the Mexicans. Polk was so greedy for land that he was willing to risk blood shed and death of his citizens for revenge against the rejection of a proposed treaty and his want for manifest destiny. Quite possibly the strongest of all reasons that the US was unjust in going to war with Mexico in 1846 was that the US forces were in the disputed territory too purposely insight the Mexicans into starting the conflict so the US would look like they were the good guys in the incident. The US troops were commanded to cross over the Nueces river to the banks of the Rio Grande. This was a move to get the Mexicans to attack US troops on land that was claimed by both countries. This did not work out as planned at first and the Mexicans wouldn’t attack. This worried Polk so he went to his cabinet. He told them on May 9, 1846 that he was to propose to congress that he wanted them to declare war on Mexico on the grounds that one: unpaid claims and two: Slidell’s rejection. These reasons were flimsy at best. But luckily for Polk word of the blood shed he had been waiting for arrived that evening. His cry for war was quickly echoed in congress and soon the declaration of war was passed. Yet this provoked attack was unjust and should have been seen as such by the US congress. This was clearly an act of aggression that was provoked by the US.
To conclude the United States was unjust in its declaration of war on Mexico in 1846. The US was clouded with dreams of Manifest Destiny. It had a president that was obsessed with fulfilling campaign promises and greed for new land. Also Polk was looking for revenge for the denial of the proposal for buying California as was evident in his original reasons for declaring war on Mexico. Also the US provoked this boarder dispute into the two-year war that it became by purposely inciting the Mexicans into a fight. All these reasons are the evidence that the US was not justified in declaring war on Mexico.