Answer:
In conclusion, the territorial dispute over the annexation of Texas and disagreements regarding boundary lines between Mexico and the United States were the primary factors that helped bring about the Mexican War. The annexation of Texas by the United States and subsequent clashes along the disputed border led to increased tensions and ultimately resulted in armed conflict between the two nations.
Step-by-step explanation:
The territorial dispute between Mexico and the United States that helped bring about the Mexican War was primarily centered around the annexation of Texas by the United States. The Mexican government had never recognized Texas as an independent nation after it declared independence from Mexico in 1836. Instead, Mexico considered Texas as a rebellious province and maintained its claim over the territory.
The annexation of Texas by the United States in 1845 exacerbated tensions between the two countries. Mexico viewed this act as a violation of its sovereignty and a direct threat to its national interests. The Mexican government refused to recognize the legitimacy of the annexation and considered it an act of aggression by the United States.
Furthermore, there were disagreements between Mexico and the United States regarding the boundary lines of Texas. Mexico claimed that the southern boundary of Texas was the Nueces River, while the United States argued that it extended to the Rio Grande. This dispute over territorial boundaries further fueled tensions between the two nations.
The situation escalated when President James K. Polk sent troops under General Zachary Taylor to occupy disputed territory between the Nueces River and the Rio Grande. In April 1846, a clash occurred between Mexican and American troops near the Rio Grande, resulting in several American casualties. The incident, known as the Thornton Affair, provided a pretext for President Polk to ask Congress for a declaration of war against Mexico.
On May 13, 1846, Congress approved a declaration of war against Mexico, marking the beginning of the Mexican-American War. The war lasted for almost two years and resulted in significant territorial gains for the United States. The Treaty of Guadalupe Hidalgo, signed on February 2, 1848, ended the conflict and established new boundaries between Mexico and the United States.
Under this treaty, Mexico ceded vast territories to the United States, including present-day California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado, Wyoming, Kansas, and Oklahoma. The acquisition of these territories by the United States further solidified its territorial expansion and marked a significant turning point in the history of both nations.