Annexation, War with Mexico, and the Texas of Eighteen Forty-Eight

On December twenty-ninth, eighteen forty-five, Texas became the twenty-eighth state of the United States. The annexation had been debated in Congress for nearly a decade, stalled by the question of slavery and the near-certainty that absorbing Texas would mean war with Mexico. President James K.

Polk decided those were acceptable risks. He was right about both of them. Mexico had never recognized Texas independence and considered annexation an act of aggression.

In April of eighteen forty-six, Mexican and American cavalry clashed north of the Rio Grande, in territory both nations claimed, and Polk used the incident to ask Congress for a declaration of war. The Mexican-American War lasted two years. American forces under General Zachary Taylor fought through northern Mexico while General Winfield Scott landed at Veracruz and marched overland to capture Mexico City itself.

The Treaty of Guadalupe Hidalgo, signed February second, eighteen forty-eight, ended the war and fundamentally remade North America. Mexico ceded roughly half its national territory: present-day California, Nevada, Utah, most of Arizona and New Mexico, and parts of Colorado and Wyoming. Texas's southern border was fixed at the Rio Grande, the boundary Mexico had always disputed.

The United States paid fifteen million dollars and assumed three and a quarter million dollars in American citizens' claims against Mexico. Whether this constituted a fair transaction or a coerced land transfer has been argued ever since. The war produced a generation of officers who would face each other again in the Civil War.

Ulysses Grant, who served as a young lieutenant in Texas before the war, later wrote that he considered the Mexican conflict one of the most unjust wars ever waged by a stronger nation against a weaker one. He wrote those words in his memoirs. He served anyway.