All of the following are true of General Sibley, except that ______________________.

General Sibley's role during the Civil War, particularly in the New Mexico Campaign, is significant in understanding his strategies and the context of Union and Confederate military engagements. While Sibley did have command over troops that included different groups of soldiers, his intention was not limited to only involving Mexican soldiers in combat.

The correct understanding is that Sibley aimed to utilize the troops available to him, which included a mix of Texas troops and volunteers, to achieve his strategic objectives in New Mexico. His recruitment of Texas Rangers and the overall organization of his forces demonstrate that he sought to maximize his military capabilities rather than restrict them to a particular demographic or ethnic group.

The other statements reflect accurate aspects of Sibley's history: he served in New Mexico before the war, recognized the disarray among Union forces, and did indeed recruit Texas Rangers for his campaign. These contextual elements help to clarify the breadth of Sibley’s military ambitions and the diverse composition of his forces, making the assertion that he wanted only Mexican soldiers in battle inconsistent with the historical record.