Question 43

The primary cause of the war between Mexico and the United States was the dispute over the Texas-Mexico border.

The conflict stemmed largely from disagreements regarding the southern boundary of Texas, which had been annexed by the United States. This territorial dispute escalated tensions and ultimately led to the outbreak of war.

A) Raids across the Mexico-United States border by Pancho Villa

This option is incorrect as it refers to events that occurred much later, specifically in the early 20th century. Pancho Villa's raids were not related to the causes of the Mexican-American War, which occurred from 1846 to 1848.

B) Dispute between the United States and Mexico over the Texas-Mexico border

This is the correct answer. The annexation of Texas by the United States in 1845 led to a significant dispute regarding the border, as Mexico claimed the Rio Grande as its boundary, while the United States asserted that the border lay at the Nueces River. This disagreement was a central factor that ignited the war.

C) California's admission to the Union

While California's admission to the Union was a significant event in American history, it occurred after the war and was not a direct cause of the conflict. The war had already started due to the border disputes and territorial ambitions.

D) The occupation of Veracruz by United States naval forces after the arrest of several United States marines

This option is also incorrect as it pertains to events that occurred later during the war. The occupation of Veracruz was a military action taken by the United States, but it was not a primary cause of the war itself.

Conclusion

The dispute over the Texas-Mexico border was the key catalyst for the Mexican-American War, making option B the definitive correct answer. In contrast, the other options either reference events that occurred after the war or are unrelated to the initial causes of the conflict, highlighting their incorrectness.