The Mexican-American War was controversial, but others said it was meant to occur. President James K. Polk, known for expanding territorial land of the United States, believed Americans should have power over the entire North American continent.
The war started in 1846 when Polk, who was president at that time, wanted to buy land that belonged to Mexico. Polk sent John Slidell, an American diplomat, to offer $30 million for the land. The only problem was that the Mexican government was not interested and turned down the deal. Polk became furious and sent American troops to a disputed area between the Rio Grande and the Nueces River in January 1846. Before the war began, there already was conflict on whether Texas ended at the Nueces or the Rio Grande. After sending troops, Polk tried to incite Mexico into war, and soon enough the Mexican government responded by crossing the Rio Grande and firing on American troops in April 1846. In response, Polk sent an order for war to Congress on May 11, 1846. Polk declared, “Mexico has invaded our territory and shed American blood upon American soil."
It was a very questionable move that was heavily criticized by Northerners. Many Northerners believed that Polk only wanted the land to extend slaveholding. Others thought it was unfair to take Mexico’s land by force. Second Lt. Ulysses S. Grant was one of the people who gave his own opinion on the war by saying it was “one of the most unjust ever waged by a stronger against a weaker nation.” The war was compared to European monarchy wars.
Apart from all the arguing about whether it was right or wrong, the U.S. was successful on the battlefield. However, many soldiers died due to poor sanitation and illness such as yellow fever. After all the fighting, General Winfield Scott and his army occupied Mexico City in September 1847, ending the military conflict.
Polk then started negotiations about the land with Mexico’s government. Polk sent Nicholas Trist, a chief clerk in the State Department, to settle the treaty between the two countries. The Mexicans accepted the $15 million offer, leading to the Treaty of Guadalupe Hidalgo which was signed on February 2, 1848. The treaty was approved by the U.S. Congress shortly after. The United States obtained new territory, including New Mexico, Utah, Nevada, Arizona, California, Western Colorado, and Texas.
Although the U.S. won, controversy spread about whether slavery would spread to the new territories. The U.S. held more power than Mexico and was stronger in many cases. Ultimately, many think it was absurd for Polk to declare war for a battle he provoked and started.