During the period of 1844 to 1877 in United States history, the Mexican-American War was a significant conflict that arose from territorial disputes between the United States and Mexico. This war, which lasted from 1846 to 1848, played a crucial role in shaping the borders of the modern United States. Understanding the causes and consequences of this war is essential for evaluating its impact on American expansion. Which of the following statements best describes a cause of the Mexican-American War?