II.

Background

The two major issues behind the war were the inability of the Mexican government to establish political and economic control over its vast northern frontier, including the Mexican state of Tejas y Coahuila, and the westward movement and dynamic expansionism of the United States during the 19th century.

A.

Lack of Mexican Control

Under Mexico’s first national charter, the constitution of 1824, the territories of Coahuila and Texas were established as one Mexican state: Tejas y Coahuila. However, the central government in Mexico City had enormous difficulty exercising direct control over events in these northern regions of the country, due to a variety of problems. The most important of these were civil war and religious turmoil.

The 1820s and early 1830s saw a number of military rebellions in Mexico in which federalists, who supported constitutional democracy and wanted to limit the power of the Roman Catholic Church, clashed with centralists, who wanted a centralized dictatorship based in Mexico City and opposed reforms intended to weaken the church. In 1835 the federal republic was overthrown by centralists. The next year the 1824 constitution was replaced by laws which concentrated political power in the capital and took power away from the states. For the next decade, various competing factions of centralists controlled the Mexican government. The political turmoil of this period, as well as the centralization of power in Mexico City, made it difficult for the Mexican government to exercise its authority in the northern frontier regions such as Texas.

This weak political control was matched by the decline of Catholic religious authority in the region in the late 1700s and early 1800s. In the 18th century, the Spanish Crown moved to limit the wealth and power of Franciscan and Jesuit religious orders by taking over much of their property. The Jesuits were expelled from the Spanish colonies in 1767, and their buildings and property were auctioned off by the Crown. The federalists who wanted to limit the power of the Catholic Church were also hostile to the Franciscan order, which caused many Franciscans to flee to Europe.

By the 1820s the number of missionaries in the northern frontier regions had dropped off sharply. The Catholic Church did not have the funds nor the clergy to fill the void after the Jesuit and Franciscan missionaries left the frontier. By 1846 the church’s presence on the Mexican frontier had diminished, with empty parishes in places where friars once proudly served. Because one of the primary goals of the missionaries was to convert Native Americans to Christianity and pressure them to adopt Hispanic customs, the decline of the religious orders also meant a decline in the influence of Hispanic culture and Catholicism in the region.

B.

U.S. Expansion

After 1821 the northern regions of Mexico became increasingly integrated with the United States. Before Mexico won independence from Spain in 1821, Spain had forbidden trade between Santa Fe, in the New Mexico territory, and the United States. After independence, Mexico began to encourage trade. The inauguration of the Santa Fe Trail in 1821 linked Independence, in western Missouri, to Santa Fe and extended the Missouri trade into Chihuahua, a city in north central Mexico. This growing trade led the northern Mexican provinces to seek manufactured goods from the United States rather than areas in southern Mexico.

At the same time, the United States was expanding aggressively. President James K. Polk (1845-1849) and his administrators sought trade outlets to the Pacific Ocean and had their eyes on the coasts and bays of Texas, Oregon and California. Land-hungry settlers were moving across the Mississippi River into the cotton fields and cattle lands of Louisiana and East Texas. Fur trappers and New England merchants were looking for pelts and hides along the Gila River—which runs through the current U.S. states of Arizona and New Mexico—and moved from there into southern California.

The westward migration of U.S. citizens was encouraged by Manifest Destiny, a belief that territorial expansion by the United States was both inevitable and divinely ordained. Those who believed in Manifest Destiny also believed that the culture of the United States was superior to other cultures and that republican forms of government and democracy should be expanded in order to “civilize” other peoples. Although Manifest Destiny was criticized by some people as blatantly racist, it enjoyed support among U.S. citizens and politicians in the mid- and late 1800s.