Rather than breaking Cheyenne resistance and opening Colorado to American settlement, the massacre inflamed resistance across the northern and southern plains.

The news of what had happened at Sand Creek — carried by survivors and by the warriors who had been away from the camp — spread quickly.

The Cheyenne Dog Soldiers, the most militant of the Cheyenne military societies, responded with raids across a wide area of the central plains.

The Lakota and Northern Cheyenne joined in.

The violence of 1865 was substantially more widespread and destructive than the violence of 1864, precisely because Sand Creek had destroyed the credibility of the peace faction within the Cheyenne nation.

Why would anyone seek peace with a government whose soldiers attacked friendly camps while flying the American flag?