During the Mexican-American War, Mexican General Santa Anna surrounds the outnumbered forces of U.S. General Zachary Taylor at the Angostura Pass in Mexico and demands an immediate surrender. Taylor refused, allegedly replying, "Tell him to go to hell," and early the next morning Santa Anna dispatched some 15,000 troops to move against the 5,000 Americans. The superior U.S. artillery was able to halt one of the two advancing Mexican divisions, while Jefferson Davis' Mississippi riflemen led the defense of the extreme left flank against the other Mexican advance. By five o'clock in the afternoon, the Mexicans begin to withdraw. The Mexican-American War began with a dispute over the U.S. government's 1845 annexation of Texas.
In January 1846, President James K. Polk, a strong advocate of westward expansion, ordered General Taylor to occupy disputed territory between the Nueces and Rio Grande rivers. Mexican troops attacked Taylor's forces, and in May 1846 Congress approved a declaration of war against Mexico. At Buena Vista in February 1847, and at Monterrey in September, Taylor proved a brilliant military commander, earning the nickname "Old Rough and Ready" while emerging from the war a national hero. He won the Whig presidential nomination in 1848 and defeated the Democratic candidate, Lewis Cass, in November. The other hero of the Battle of Buena Vista, Jefferson Davis, became secretary of war under President Franklin Pierce in 1853 and president of the Confederate States of America in 1861.