11. The campaign in New Mexico was a Confederate failure
Sibley’s campaign in the American Southwest was a series of Confederate military victories in battles that were small in relation to the bloodbaths unfolding in Virginia, Maryland, and Tennessee in 1862. The skirmishes were nearly all Confederate victories, though pyrrhic in nature, as their supplies dwindled to the point an army in the field could no longer be sustained. Silas Soule served throughout the campaign with distinction, rising in rank within the Colorado Volunteers. The largest battle of the campaign, at Glorieta Pass in New Mexico, saw the Union troops driven from the field by Confederates who were then forced to withdraw.
The Colorado Volunteers returned to the Colorado Territory in the fall of 1862, with Soule assigned to serve as adjutant to Colonel John M. Chivington, who had his headquarters in Denver. Soule had by then risen to the rank of Lieutenant of Volunteers. In 1864, promoted to Captain, he was reassigned to the command of Major Edward Wynkoop, to serve as his second-in-command at Fort Lyon. The fort was located on the Arkansas River, in the southeast corner of Colorado. As well as maintaining a garrison to defend against Confederate incursion, Fort Lyon was necessary to protect the territory against the Arapaho and Cheyenne natives who preyed on the cattle herds of settlers.