The Mexican–American War was an armed conflict between the United States and Mexico from 1846 to 1848 in the wake of the 1845 U.S. annexation of Texas, which Mexico considered part of its territory despite the 1836 Texas Revolution.
In addition to a naval blockade of the Mexican coast, American forces invaded and conquered New Mexico, California and parts of northern Mexico. Another American army captured Mexico City, forcing Mexico to agree to the sale of its northern territories to the U.S.
Territorial expansion of the United States to the Pacific coast was the goal of President James K. Polk, the leader of the Democratic Party[1]. However, the war was highly controversial in the U.S., with the Whig Party and anti-slavery elements strongly opposed. The major consequence of the war was the Mexican Cession of the territories of California and New Mexico to the United States in exchange for $15 million. Mexico accepted the Rio Grande as its national border, and the loss of Texas. Meanwhile gold was discovered in California, which immediately became an international magnet for the California Gold Rush. The political aftermath of the war raised the slavery issue in the U.S., leading to intense debates that pointed to civil war; the Compromise of 1850 provided a brief respite.
In the U.S. the conflict is often referred to as the Mexican War and sometimes as the U.S.–Mexican War.[2] In Mexico, terms for it include (primera) intervención estadounidense en México ((first) American intervention in Mexico), invasión estadounidense de México (American[a] Invasion of Mexico), and guerra del 47 (The War of '47).