From The Comanche Empire, by Pekka Hämäläinen (Yale U. Press, 2008), pp. 198-199:
By the mid-1830s, it was clear that the Indian policy of Texas was a complete failure. The decision to open the province to American immigrants had backfired. Rather than moving to the interior to shield the province’s core areas around San Antonio from Comanche attacks, most Americans stayed east of the Colorado River, beyond the Comanche range and within an easy reach of Louisiana, their main commercial outlet. The result was a splintering of Texas into two distinct and increasingly detached halves. The Anglo-dominated eastern half experienced steady growth, developing a flourishing export-oriented cotton industry and spawning nearly twenty new urban centers by 1835. This half was part of Mexico only in name. It main economic and political ties extended eastward to the powerful mercantile houses of New Orleans, and its settlers often spoke no Spanish, held slaves in spite of a widespread aversion toward the institution in Mexico, and harbored separatist sentiments.
The Tejano-dominated western half, meanwhile, descended into underdevelopment. As raids and violence engulfed vast portions of western and southern Texas during the early 1830s, basic economic functions began to shut down. Villages and farms were stripped of livestock and the reviving ranching industry faltered once again. Agriculture deteriorated as farmers refused to work on fields where they were exposed to attacks. Laredo on the lower Rio Grande lost one-sixth of its population between 1828 and 1831 to Comanche raids, nearly expiring during a cholera outbreak in 1834. Settlers lived in perpetual fear and near-starvation even in San Antonio, where, in the words of one observer, “nothing can be planted on account of the Comanches and Tahuacanos [Tawakonis] who frequently harass the city even in time of peace.” Villages curled inward and grew isolated, for settlers “seldom venture more than a mile from town on account of the Indians.” Major roads leading to San Antonio were frequently cut off, and Berlandier traveled on deserted roads lined with crosses marking places “where the Comanches had massacred travellers or herdsmen.” The road from Coahuila to Texas crossed “an uninhabited country” where Indian raiders ruled, and commercial and political links between New Mexico and Texas existed only on paper. When assessing the long-term impact of Comanche raids on western and southern Texas, Berlandier depicted a decaying, psychologically disfigured captive territory. …
It was this divided Texas that in 1835 rebelled against the central government and in 1836 became an independent republic with close ties to the United States. The Texas Revolution was the product of several long-simmering problems, which came to a head in 1834 and 1835 when the military strongman Antonio López de Santa Anna assumed dictatorial powers in Mexico City and imposed a conservative national charter known as Las Siete Leyes. Las Siete Leyes ended the federalist era in Mexico and ushered in a centralist regime bent on curtailing states’ rights and sovereignty. The momentous shift galvanized Texas, turning the smoldering tensions over slavery, tariff exemptions, and immigration (further immigration from the United States had been banned in 1830) acute and then violent. When centralist forces marched into Texas in fall 1835 to rein in the renegade province, they faced unified resistance that included the vast majority of Anglo colonists and many prominent members of the Tejano elite. In November, delegations from twelve Texas communities met in San Felipe de Austin, declared allegiance to the federalist constitution of 1814, and cut off ties to the centralist regime.
Texas independence may have been predetermined by geography—Texas was simply too far from Mexico City and too close to the United States—but the event can be fully understood only in the larger context that takes into account the overwhelming power and presence of the Comanches in the province in the years leading to the revolt.