What was the primary consequence of the Texas annexation to the United States?

The primary consequence of the Texas annexation to the United States was indeed the increased tensions leading to the Mexican-American War. When Texas joined the Union in 1845, it was a significant factor in heightening unresolved border disputes between the United States and Mexico. The annexation, viewed by Mexico as an act of aggression and a violation of its sovereignty, intensified existing hostilities.

Mexico had not recognized Texas's independence since it had been declared a republic in 1836, and the annexation spurred Mexico to act aggressively, culminating in the outbreak of the Mexican-American War in 1846. This conflict dramatically altered the territorial boundaries of the United States, leading to substantial land gains for the U.S. through the Treaty of Guadalupe Hidalgo in 1848, which included present-day California, Arizona, New Mexico, and Texas.

In contrast, while there may have been a reduced military presence in certain areas following annexation, this was not the defining consequence. The notion of an economic downturn is also misleading, as the annexation ultimately led to economic development through new resources and land. Immediate statehood might be a compelling point, but it was the resultant geopolitical repercussions that stand out as the primary consequence of the annexation. The intertwining