Releasing the horses on the Plains would have immediately undermined that objective — the families would have begun catching them within hours of the army’s departure.

The calculation was coldly practical.

The horses that could not be absorbed into army use were a military asset that belonged to the enemy.

In military logic, an asset that cannot be captured should be destroyed.

Mackenzie’s choice to destroy the horses was the extension of the same logic that burned the lodges and the food.

The goal was not to kill the people in the canyon.

The goal was to eliminate the material basis on which resistance was possible.