War of a Thousand Deserts: Indian Raids and the U.S.-Mexican War/The Comanche Empire

[...]the Comanche empire crippled Spain and Mexico, and because of that weakness, especially as Americans perceived it, the United States invaded Mexico in 1846. The Indians' supreme equestrianism, decentralized social structure, military prowess, knowledge of the land, and leverage in a commodity exchange network that spanned the mid-continent enabled native groups to exploit this vast region populated by dispersed towns, ranches, and settlements.