On May 11, 1846, President James K. Polk asked Congress to declare war on Mexico. This request was a culmination of months of tension between the two nations, primarily centered around a dispute over the border between Texas and Mexico.
Polk had been elected president with a mandate to expand American territory. He believed that the United States had a manifest destiny to stretch from sea to shining sea, and he was determined to make that a reality. One of the areas Polk was particularly interested in was Northern Mexico, including modern-day California, Arizona, New Mexico, and parts of Colorado, Utah, and Nevada. However, these lands were controlled by Mexico, and they showed no signs of willingly giving them up.
The situation between the two nations began to escalate when Texas joined the United States in 1845. However, Texas and Mexico disagreed on where their border was, with Texas claiming that it extended all the way to the Rio Grande, and Mexico insisting that the actual border was the Nueces River, 150 miles to the north.
Polk, eager to secure the land he wanted, sent troops into the disputed area between the Nueces River and the Rio Grande. He instructed the soldiers to defend themselves if necessary, but to avoid provoking a conflict if possible. However, Mexican troops under General Mariano Arista attacked an American patrol on April 25, killing eleven soldiers and capturing dozens more.
This attack gave Polk the pretext he needed to ask Congress to declare war. In his message to Congress, Polk framed the conflict as necessary to defend American sovereignty and avenge the deaths of American soldiers. He argued that war was the only way to resolve the longstanding differences between the two nations and secure American expansion into the desirable western lands.
Congress ultimately granted Polk’s request, and the United States went to war with Mexico. The war lasted for two years and resulted in a decisive American victory, including the acquisition of the territories Polk had been eyeing. However, the war also had significant human costs, with thousands of Mexican and American lives lost.
The decision to go to war with Mexico remains controversial to this day. Some argue that the conflict was justified, necessary for American expansion and defense. Others view it as an imperialistic land grab, an unnecessary and brutal war that cost countless lives. Regardless of one’s position, there’s no denying that Polk’s request to Congress on May 11, 1846, was a turning point in American history, setting the stage for one of the major conflicts of the 19th century.