Alta California and Santa Fe de Nuevo Mxico were captured soon after the start of the war and the last resistance there was subdued in January 1847, but Mexico would not accept the loss of territory. How did once-dominant Mexico lose the Mexican-American War? settlement, frightening the inhabitants away, leaving their At that time, only about 75,000 Mexican citizens lived north of the Rio Grande. Mexico was essentially broke. properly organized volunteerswould invade, overrun, and Between 1846 and 1848, the United States of America and Mexico fought a war known as the Mexican-American War. Beyond the disputed area of Texas, U.S. forces quickly occupied the regional capital of Santa Fe de Nuevo Mxico along the upper Rio Grande, which had trade relations with the U.S. via the Santa Fe Trail between Missouri and New Mexico. Mexicans who opposed direct conflict with the United States, including President Jos Joaqun de Herrera, were viewed as traitors. How and why did Texas gain its independence from Mexico? challenges president Polk to name the exact "spot" The failure of the Wilmot Proviso only put off the issue of slavery for so long. it is "Our, James Polk promises Texas he will support moving the All Rights Reserved. // -->