What were the long-term effects of the Mexican-American War?
With the introduction of new states, as well the potential for many more in the newly conquered territories, the delicate balance between slave states and free states was threatened. Each side was afraid of losing political power to the other, and as tensions grew so did the threat of secession. The Mexican-American war also served as a training ground for many officers who would later lead men on both sides of the Civil War, such as Ulysses S. Grant and Robert E. Lee.
