Mexican War/United States Land and TerritoryThe Mexican-American War caused many casualties and could have been avoided. President Polk wanted more land and liked the idea of ​​expanding the United States. As a result of the war, the United States acquired more than 525,000 square miles of land. Many historians believe that the Mexican War was an unnecessary attack on a weaker country. The Mexican War had many causes and effects, but Mexico ultimately lost. The Mexican-American War happened for many reasons. Around 1835, Texas opposed the Mexican government. “One of these disputes was over the Texas-Mexico border issue (Downey).” The Mexican government then owned Texas. In 1844, James Polk was elected president. "More important was the growing sense in the United States that the country had a 'manifest destiny' to expand westward into new territories (Downey)." He really liked the idea of ​​expanding the United States and for this reason he supported the annexation of Texas. Texas became a state in 1845 and Mexico severed all relations with the United States. The United States also said Mexico owed $3 million to compensate for the loss of life and property. The Americans demanded that they seize it by force. There were many reasons that caused the Mexican War. The Americans had two goals: more land and to invade Mexico. The United States wanted land it had asked Mexico to sell. “Despite all American victories, Mexico refused to negotiate a peace treaty (Downey).” They wanted to invade Mexico to force the Mexicans to accept that they had lost their land. “The United States paid $15 million for land” (Downey). Mexicans living on land were to be treated like American citizens. Mexico lost 2/3 of its pre-war territory, including Texas. America took California, Nevada, Utah and Colorado. .... middle of document ......n goals of the war, more land and invade Mexico. America gained a lot of land and also revived the idea of ​​slavery. The United States gained the regions of California, Nevada and Utah. They also acquired most of Arizona, New Mexico, and parts of Colorado and Wyoming. Many historians believe that the Mexican War was unnecessary and an unnecessary attack on a weaker country. : The Mexican War and after. Combat Studies Institute Press, 2007. Web, March 13, 2014. “Timeline of the Mexican-American War.” Timeline of the Mexican-American War. com. A&E Television Networks. Web, March 14, 2014. “Mexican War.” World Book Online World Book, 2014. Web.. 2014.