Upon America’s declaring war with Mexico in May 1846, President James Polk sent “the Army of the West” to New Mexico. See Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 758. This army was sent for the sole purpose of conquest, and it was led by Brigadier General Stephen Watts Kearny. Id.
The Army of the West “included 648 regulars and 1,000 Missouri volunteers, with 16 cannons and enormous supply trains consisting of 1,556 wagons, 459 horses, 3,658 mules, and 14,904 oxen and cattle.” Id. It was an illustration of the logistical capability of the American military. Id. citing K. Jack Bauer, The Mexican War (New York, 1974), 127-34.
This formidable force marched into New Mexico, occupying the territory for the remainder of 1846. Then, on January 17, 1847, the Pueblo Native Americans and Mexicans rebelled against their occupiers. Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 761. However, the uprising was quickly put down, and for the following four years, the territory of New Mexico would effectively be a military dictatorship. Id.
This only changed as a result of the Compromise of 1850, where New Mexico was given a legitimate territorial government. Id. at 762. As of the time of annexation, there were approximately 50,000-60,000 individuals living in New Mexico, and of those, only about 1,000 were Anglo-American. Id. citing Howard Lamar, The Far Southwest (New York, 1970), 56-65. At that time, New Mexico was more populated than California or Texas, the two other pieces of territory that were involved in the Mexican-American War. Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 762.
America’s taking of New Mexico, while fulfilling the dream of many Americans of manifest destiny, was aggressive and cavalier. President Polk’s strategy for the Mexican-American War, with the taking of California, New Mexico, and the northern parts of Mexico just south of Texas, was proving to be highly effective as the Mexican-American War broke out.
However, these actions were setting a precedent. While some Americans may have viewed their country as a modest republic in a world of empires and monarchies, with the Mexican-American War, America was showing its imperial tendencies as well. In retrospect, this is abundantly clear from the fact that New Mexico had a sizable population of 50,000-60,000, far from being the wild, unsettled land that perhaps some modern Americans imagine to have been in existence at that time.
These imperial tendencies, whether admired or disdained, ensured that America would expand its borders at a rapid pace and make its presence felt not just throughout North America but the world.