My students always leave the lesson about the U.S. – Mexico War with more questions than answers, which to me is exactly right. They are always surprised to hear about the opposition to the war from people like Frederick Douglass, Henry David Thoreau and Abraham Lincoln, not to mention the desire to avoid conflict from most Mexicans and Native people.
The invasion of Mexico and theft of their property is the start of a long trend of expansion by conquest. The seeds planted here by Polk and Tyler would be harvested by McKinley and Roosevelt in the Spanish-American War as well as future imperialist adventures all over the globe.
Students recall this activity throughout the year. It is a powerful reminder that individual choices form the course of history.