To form your judgment and write your essay, you should consider the following points:
1. The Root of the Conflict: The Mexican-American War was sparked by a dispute over the southern border of Texas. The United States claimed the Rio Grande as the border, while Mexico claimed the Nueces River farther north. This disagreement stemmed from conflicting agreements made at the end of the Texas war for independence in 1836.
2. Texans' Actions: Texas came to exist through a series of actions by American settlers. These settlers migrated to Texas and eventually sought independence from Mexican rule. The Texan perspective emphasized their desire for self-governance and expansion of their territory.
3. Differences in Perspectives: After the Texas war for independence, Texan and Mexican perspectives differed on the status and borders of Texas. Texans believed in their right to independence and supported the idea of Texas joining the United States. Meanwhile, the Mexican government viewed Texas as a rebellious province and maintained that it was still part of Mexico.
4. Beginning of the Mexican-American War: The Mexican-American War began in 1846 when the United States sent troops into the disputed territory between the Rio Grande and Nueces River. Mexico saw this as an invasion of its territory, while the United States justified its actions based on its interpretation of the border.
5. Course of the War and Results: The war lasted for two years and resulted in significant territorial gains for the United States. The Treaty of Guadalupe Hidalgo, signed in 1848, officially ended the war and established the Rio Grande as the border between Texas and Mexico. Mexico lost approximately half of its territory to the United States, including present-day California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado, Wyoming, Kansas, and Oklahoma.
Considering these points, you can form your judgment and write your essay by analyzing the different perspectives and arguments presented by each side. Assess the historical accuracy of the facts presented and consider the motivations, actions, and consequences of the war. Ultimately, you will need to present a reasoned argument on whether or not you believe the Mexican-American War was justified.