They were wrong in their optimism about the American political system’s ability to produce consistent, good-faith implementation of its own commitments.

The failure of the peace strategy was not primarily the fault of the peace chiefs who pursued it.

It was primarily the fault of the political system that failed to honor its commitments.

The peace chiefs were trying to make work a system that the American political class said it believed in but did not actually implement consistently.

Black Kettle’s specific failure — his death in the second surprise attack on his camp — is the most dramatic illustration of this systemic failure.

A man who had done everything the American government asked, who had moved his band to the assigned reservation area, who had sought protection from American officials, was killed by American soldiers in his sleep.