Here is a map of the United States in 1840, six years before the War.
And this is a map from 1870. At this time, much of the land taken from Mexico has become "US territories" (shown in light blue). The "territories" will later become states. Why did the war happen?
The main reason for the war was the idea, very popular among American politicians, that American had a "manifest destiny" to conquer all the land to the Pacific Ocean (where California is today). This means that President Polk and many others believed that God had given them the right to destroy all people who opposed their plans to expand the United States to the West.
How did the war start?
To gain support for the war, the U.S. President, James Polk, sent soldiers into Mexico, hoping they would be attacked. Some of them were. In the spring of 1846, 16 soldiers were killed while trespassing in Mexico. The President claimed that they were killed in the United States and, by this lie, he got the support of many Americans. Abraham Lincoln asked the President to show the exact spot (or place) where they were killed, but the President never did.
Moreover, in those years, many Americans developed racist attitudes towards Mexicans, and this racism helped to support the war against Mexico.
How many people were killed?
The United States lost 13,780 people. Many of them were German and Irish immigrants who fought for the United States only to get money.
About 25,000 Mexicans were killed; most of them women, children, and other non-fighters. The United States bombed Mexican cities.
What were some consequences?
Famous Americans such as Ralph Waldo Emerson, former president John Quincy Adams, and Henry David Thoreau protested against the war. The anti-war movement was also an anti-slavery movement. At the end of the war, Texas became a slave state. New US territory included Texas, California, Nevada, Arizona, New Mexico, and Utah. The United States took 40% of Mexican land.
Philip Adamek
