Answer :
Answer:
The Mexican-American War was an military conflict between Mexico and the USA caused by the latter's occupation of the state of Texas. The fighting had to do with America's strong feelings of nationalism justified by Manifest Destiny, which was the belief that the country was destined by God to expand its territory. Besides, the south needed more southern states to spread out slavery, since it was forbidden in the northern states. Thus, because the Mexican government refused to sell the state of Texas, the US president James K. Polk decided to declare war on Mexico.