Treaty of Guadalupe Hidalgo
The Treaty of Guadalupe Hidalgo was signed on February 2, 1848, and marked an important event in American history. Officially, the document is titled the Treaty of Peace, Friendship, Limits and Settlement between the United States of America and the Mexican Republic and it was the treaty that put an end to the Mexican War (1846-1848). It was this document that drew the border between the United States and Mexico at the Rio Grande and the Gila River, and that established the purchase of the territories of Arizona, Colorado, Nevada, New Mexico, Utah, Texas and California by the United States from Mexico.
It was the Treaty of Guadalupe Hidalgo that officially completed the territorial expansion of the United States.
On May 13, 1846, the United States declared war on Mexico as the two countries disputed the territory of the Republic of Texas, which had won independence from Mexico in 1836. Tensions between the two countries had been high since 1845, when Texas was admitted into the Union by President James Polk. The biggest conflict was over which borders belonged to which country, and American troops occupied the lands between the Nueces and the Rio Grande after the Mexican government refused to sell California and New Mexico to the United States.
Texas saw this as an act of aggression against their country and set their troops across the Rio Grande. This was seen as an invasion of American soil, and President James Polk declared war on Mexico.
The war lasted almost two years, until the defeat of the Mexican army and the fall of Mexico City in September 1847. The Treaty of Guadalupe Hidalgo was signed on February 2, 1848, and officially ended the Mexican War. Mexico was forced to give up their claims to Texas and recognize the Rio Grande as America's southern boundary between Texas and Mexico. The United States also gained 525,000 square miles of territory. In return, the United States paid $15 million to the Mexican government.
The Aftermath of the Treaty of Guadalupe Hidalgo
With the signing of the treaty Mexicans living in the newly purchased territories were offered U.S. citizenship. If they chose to remain Mexican citizens they would have to relocate back to Mexico. While the treaty had provisions that promised to protect the rights of the thousands of Mexicans who lived in the now-American territories, their ways of life came under attack and they were discriminated by the new settlers, which caused decades of conflict.
Abolitionists also opposed the Mexican War and the signing of the treaty, as new land would mean that slavery would be expanded into new territories as well. Bills were presented to Congress asking that slavery was prohibited in any territories acquired by the United States after the war, but the bills did not pass. So, even though the Treaty of Guadalupe Hidalgo ended the Mexican War, it fostered the war over slavery that was happening in the United States, which led to the outbreak of the Civil War (1861-1865).