Who was instrumental in the campaign against the Navajo in the 1860s?

James Carleton played a critical role in the campaign against the Navajo in the 1860s, particularly during the period of the Long Walk. As a Union general and the military commander of the New Mexico territory at the time, Carleton was tasked with implementing strategies to subdue the Navajo people. He oversaw military operations aimed at breaking the resistance of the Navajo, which included attempts to starve them into submission by destroying their crops and livestock.

Carleton also authorized the forced removal of the Navajo from their homeland in 1864, leading to their relocation to the Bosque Redondo. This campaign was marked by significant hardship and suffering for the Navajo people, as they were subjected to a long and treacherous walk to the internment site. The actions taken under Carleton's command were pivotal in the U.S. government's efforts to control the region and were foundational to the complex relations between Native American tribes and the federal government in the following years.

The other figures mentioned, while notable in their own right, did not have the same direct involvement in the campaign against the Navajo during this specific timeframe.