"The undersigned enters New Mexico with a large military force for the purpose of seeking union with and ameliorating the condition of its inhabitants...It is enjoined on the citizens of New Mexico to remain quietly at their homes, and to pursue their peaceful avocations. So long as they continue in such pursuits, they will not be interfered with by the American army, but will be respected and protected in their rights, both civil and religious."

In 1846 the United States claimed as its territory the land between the Nueces River and the Rio Grande, by virtue of prior claim by the newly-annexed Republic of Texas. By the same token, so too did it maintain that the annexation of Texas gave the U.S. title to what is now the eastern half of present-day New Mexico.
Accordingly, just as General Zachary Taylor had been sent to the assert American sovereignty over the "Nueces Strip," so too was Colonel (soon to be Brevet Brigadier-General), Stephen Watts Kearney, sent to occupy New Mexico. Unlike Taylor, Kearney had not one, but two missions: First, secure New Mexico; Second, continue westward and conquer Upper California. This was a land, according to Secretary of War William L. Marcy, where the people, particularly the American settlers residing in the Sacramento River valley, were "well disposed towards the United States."

    Kearney was at Fort Leavenworth when he received his orders in June 1846. At that time he was assured the state of Missouri was raising a volunteer force to supplement the regulars under his command. To do this Kearney sent Capt. James Allen, of the First Dragoons, to the Mormon camps. There, the persuasive Allen was successful in raising an entire battalion. In June, before Allen was able to join him with his newly-raised "Mormon Battalion," Emory. Following the well-worn Santa Fé Trail  Kearney's forces marched and rode across the vast open plains of central U.S.A. Near the end of July they reached Bent's Fort, a private, fortified trading post located in present-day southern Colorado. The Mexican governor of New Mexico, General Manuel Armijo, learning that Kearney was on the march responded on August 8th by issuing his proclamation at Santa Fé, in which he declared he was "willing to sacrifice his life and all his interests in the defense of his country."