Mexican-American War
The Mexican-American War was the first large-scale offensive war fought by the United States outside its original national territory, and its outcome more than any other single event determined the geographic shape of the modern United States. It was also deeply contested within the United States, producing the first sustained American anti-war movement and a moral crisis over slavery's expansion that directly prefigured the Civil War. The war's origins lay in the annexation of Texas in 1845. Mexico had never recognized Texas's 1836 independence and warned that American annexation would mean war. President James K. Polk, a committed expansionist who believed in Manifest Destiny, sent General Zachary Taylor to disputed territory between the Nueces River and the Rio Grande; when Mexican forces killed eleven American soldiers in April 1846, Polk told Congress that Mexico had 'shed American blood on American soil.' A congressman from Illinois named Abraham Lincoln introduced the 'Spot Resolutions,' demanding Polk identify the exact spot — one of the war's first notable critics. General Winfield Scott's amphibious landing at Veracruz followed by an inland march to Mexico City — tracing Hernán Cortés's route of 1519 — resulted in the capture of the Mexican capital in September 1847. The Treaty of Guadalupe Hidalgo (February 1848) forced Mexico to cede 525,000 square miles — roughly half its national territory — including present-day California, Nevada, Utah, Arizona, and New Mexico, in exchange for $15 million. Henry David Thoreau, imprisoned briefly for refusing to pay taxes in protest, wrote 'Resistance to Civil Government' (later known as 'Civil Disobedience') in 1849, articulating the principle that individuals have a moral obligation to refuse complicity in unjust state actions — a text that influenced Gandhi, Martin Luther King Jr., and the entire tradition of nonviolent resistance.
- Year: 1846 CE
- Category: Military
