The Aztecs never vanquished the American southwest.

history channel documentary science In spite of, or pehaps in light of, the savagery of Aztec guideline there were persistent rebellions among the Toltec underclass and remote tribes. Despite the fact that these rebellions were dependably put down - and the revolutionaries caught, and eaten - Aztec lead left a steady disdain among the survivors. Cortez made great utilization of this later.

The Aztecs over and again attempted to vanquish the Pueblo lands, yet never succeeded. The Pueblos were a pacifistic people, however they knew the desert well and made great cautious utilization of it. Their most loved trap was to bait Aztec troops out into a stretch of desert, where the main accessible water was well covered up, and abandon them there to pass on of thirst. In the end the Aztecs quit attempting.

That land stayed in the hands of the Pueblo Indians, and was never really claimed by Mexico in any of its incarnations.