Beginning with the arrival of the Army of the West in 1846, a large military force became a permanent fixture in the territory. At first, the strong military presence was to secure New Mexico as U.S. territory. Between 1848 and 1853 troops remained to guarantee the promise made in Article XI of the Treaty of Guadalupe Hidalgo that the U.S. military would prevent nomadic peoples from making incursions into Mexico. U.S. military leaders quickly realized, however, Article XI was virtually impossible to enforce. In the negotiations over the Treaty of La Mesilla in 1853, James Gadsden also achieved the annulment of Article XI along with the addition of the Mesilla strip to the United States.
As soon as the Army of the West arrived in New Mexico, Kearny guaranteed nuevomexicanos and Pueblos safety against Navajo, Apache, Ute, and Comanche raids. After 1853, the federal army erected forts and attempted to make good on the promise. Over the next several years, various military commanders and federal Indian Agents came and went. At times the same man filled both posts; at others the offices were separated. Governor John M. Washington, for example, served as both Indian Agent and Military Governor in 1848 and 1849. His first priority was to wage war against the Navajo people in an attempt to settle long-standing conflicts between the Diné and nuevomexicanos.
Washington’s campaign only served to erode dealings between Navajos and American leaders. Following one skirmish in 1849, six Navajos were killed during an attempt to negotiate peace. One was the esteemed headman Narbona who was scalped by a U.S. militiaman. Washington’s successors followed their own distinct policies toward the territory’s indigenous peoples. Some, like Major John Munroe and Lieutenant Colonel Edwin Vose Sumner, considered the barren New Mexico territory to be a waste of American military effort and resources. Others, like Indian Agents James S. Calhoun and Michael Steck, recognized the diversity of peoples and interests in the territory and they forged positive relationships with several bands of Navajos and Apaches.
The lack of a stable and coherent “Indian Policy” at the federal level, however, stoked cultural misunderstandings and conflict. Although several bands of Chiricahua Apaches under the leadership of Mangas Coloradas struck friendly relations with Kearny in 1846, relations quickly eroded. In January 1852, U.S. forces established Fort Webster near the Santa Rita del Cobre mine (near present-day Silver City). Chiricahua warriors saw the new fort as an unsolicited and unwarranted infiltration of their homelands. Despite attempts to solve the conflict through diplomacy, a state of war existed between several Chiricahua headmen and U.S. forces throughout the early 1850s.
In the years immediately following the resolution of the U.S.-Mexico War, new forts sprang up throughout the territory. These included Fort Union on the lands of the Llaneros band of the Jicarilla Apache people, Fort Conrad to the south of Socorro, Fort Fillmore near Mesilla, Fort Stanton among the Mescaleros, and Fort Defiance in the Navajo heartland. The forts suggested Americans’ readiness to use violent force against nomadic peoples, and at times the threat of violence worked at counter purposes to Indian Agents’ overtures. Nearly 4,000 soldiers manned New Mexico’s military outposts by the close of the 1850s.