Texas Annexation - Border Disputes

Border Disputes

The joint resolution and ordinance of annexation have no language specifying the boundaries of Texas, but only refer in general terms to "the territory properly included within, and rightfully belonging to the Republic of Texas", and state that the new State of Texas is to be formed "subject to the adjustment by this government of all questions of boundary that may arise with other governments."

According to George Lockhart Rives, "That treaty had been expressly so framed as to leave the boundaries of Texas undefined, and the joint resolution of the following winter was drawn in the same manner. It was hoped that this might open the way to a negotiation, in the course of which the whole subject of the boundaries of Mexico, from the Gulf to the Pacific, might be reconsidered, but these hopes came to nothing."

There was an ongoing border dispute between the Republic of Texas and Mexico prior to annexation. Texas claimed the Rio Grande as its border, while Mexico maintained that it was the Nueces River and did not recognize Texan independence. President James K. Polk ordered General Zachary Taylor to garrison the southern border of Texas, as defined by the former Republic. Taylor moved into Texas, ignoring Mexican demands to withdraw, and marched as far south as the Rio Grande, where he began to build a fort near the river's mouth on the Gulf of Mexico. The Mexican government regarded this action as a violation of its sovereignty.

The Republic of Texas never controlled what is now New Mexico. The failed Texas Santa Fe Expedition of 1841 was its only attempt to take that territory. El Paso was only taken under Texas governance by Robert Neighbors in 1850, over four years after annexation; he was not welcomed in New Mexico. Texas continued to claim New Mexico as far as the Rio Grande, supported by the rest of the South, and opposed by the North and by New Mexico itself, until agreeing to today's boundary in the Compromise of 1850.