A People’s History of the United States: Chapter 8 Summary & Analysis

After Thomas Jefferson purchased the Louisiana Territory, the size of the United States doubled. The U.S. now bordered Mexico, which had won its independence from Spain in the 1820s. In 1836, Texas broke off from Mexico and formed its own republic; in 1845, under the presidency of James Polk, the U.S. brought Texas into the union, though the Mexican government continued to regard Texas as a part of Mexico. Polk was an expansionist president, and he ordered General Zachary Taylor (the future president of the United States) to provoke Mexican troops near the Rio Grande. In 1846, Taylor’s quartermaster was found with his head smashed in, and later, Mexican troops attacked Taylor and his men. The Mexican military had, in short, done exactly what Polk wanted them to do: they had given America an excuse to declare war on Mexico, protect Texas, and claim some of Mexico’s other territory in the Southwest. Journalists were mostly supportive of the war; one coined a term that was used to justify the fight: “manifest destiny.”

With the support of Congress, President Polk began the Mexican American War. Some politicians supported the war because they wanted to protect the troops, while others wanted to acquire more territory in the Southwest. A few, mostly from the Whig party, opposed the war for fear that war would spread slavery to the new territories. (One notable opponent of the war was Abraham Lincoln.) The American Anti-Slavery Society protested the war, and Henry David Thoreau was imprisoned for refusing to pay taxes that would be used to fund the fight. Thoreau wrote one of his most famous works, “Civil Disobedience,” to describe why he chose to go to prison. Other notable opponents of the war included Frederick Douglass and the abolitionist journalist William Lloyd Garrison, both of whom believed that new territory meant the expansion of slavery.

What was the popular opinion about the Mexican American War? There’s evidence that organized workers opposed the war, and in New York and Boston, many immigrants demonstrated against the war, calling it a “plot by slave owners.” At the time of the war, ten percent of the country was foreign-born, and their patriotism was “probably not great.” As a result, “manifest destiny” arguments probably weren’t too persuasive. Many working-class Americans joined the military and fought in Mexico, but they did so largely because they believed they stood to make money and earn property.

In Mexico’s territories, the resistance to the American military was vast. American troops took Los Angeles in the middle of 1846, but in the fall of that year there was a revolt and the military didn’t retake the region until January. American soldiers, in spite of their numerical and technological advantages over Mexico, suffered from dehydration and dysentery. During the Mexican American War, the wealthiest Americans had a vested interest in claiming Mexican territory, but instead of fighting, they sent working-class people to do so on their behalf. In all likelihood, most American troops in Mexico understood this and served resentfully.

In 1847, Mexico surrendered to the United States, and the U.S., in addition to maintaining its control of Texas, annexed a huge amount of Mexico’s territory (including modern-day California and New Mexico), greatly increasing the size of the country. This was a victory of “presidents and generals,” not American soldiers. The U.S. paid Mexico fifteen million dollars for the territory, which prompted one newspaper to claim, “We take nothing by conquest … Thank God.”