Question

Describe the events that led to the war between the United States and Mexico. Then, explain why many Americans believed that Mexico prevented them from achieving Manifest Destiny before the Mexican War.

Answer 1

It stemmed from the annexation of the Republic of Texas by the U.S. in 1845 and from a dispute over whether Texas ended at the Nueces River (the Mexican claim) or the Rio Grande (the U.S. claim).

second explanation:

Many American Indians and Mexicans disagreed that the destiny of the United States was so manifest, and some Americans saw U.S. expansion as conquest.