The Mexican-American War was based on the Americans trying to expand their territory. They thought that some parts of Mexico was a good idea so they tried to buy the lands from Mexico, using an excuse that they want payback from the Mexico's owe to America during the Spanish War. The Mexicans refused, and when they surprisingly attacked a small American station, President James K. Polk of the United States wrote a letter to the Congress to declare war on Mexico. Thus the war starts, 1846. The Americans outflanked the Mexicans in most of the battles, and when the Americans occupied Mexico City, the capital of Mexico, the Mexicans decided that if they don't agree to America's demands, they might lose even more territory. And so they peace treaty was signed at the village of Guadalupe Hidalgo, near Mexico City. As a result, the United States acquired the region we now call the Mexican Cession.…