What was a significant impact of the Mexican-American War?

The acquisition of vast territories in the west as a result of the Mexican-American War significantly reshaped the landscape of the United States. Following the war, the Treaty of Guadalupe Hidalgo in 1848 resulted in the U.S. gaining approximately 525,000 square miles of territory. This new land included present-day California, Arizona, New Mexico, Nevada, Utah, and parts of Colorado and Wyoming. This expansion not only increased the nation's landmass but also intensified the debate over slavery in the newly acquired territories, contributing to the sectional tensions that would eventually lead to the Civil War. The war and its outcomes played a crucial role in manifest destiny, the belief that the expansion of the U.S. across the American continents was both justified and inevitable.