Sheridan’s winter campaign had been approved by the Army’s command.

Custer was a commissioned officer executing ordered military operations.

The attack on Black Kettle’s camp was conducted within the forms of legitimate military authority, even though it produced results that were, in human terms, similar to Sand Creek.

The specific difference — that authorization had been provided — meant that the system did not generate the same investigation-and-condemnation response.

The normal accountability mechanisms that could recognize an unauthorized massacre could not recognize an authorized one.

This tells us something important about how authorization works as a moral shield.