This answer is not wrong.

Both men made choices that resulted in attacks on camps they had reason to believe were peaceful, and those attacks produced deaths that were preventable.

But the simplest answer is also inadequate, because it personalizes a systemic problem in ways that obscure the deeper issue.

The deeper issue was the structure of American Indian policy in this period — a structure that simultaneously asked for peace agreements and then failed to enforce them, that created military commands with the power and the will to attack peaceful camps, and that consistently prioritized the interests of settlers and territorial governments over the rights of Indigenous peoples.

Governor Evans and Colonel Chivington shared responsibility for Sand Creek, but so did the broader failure of federal oversight that left Colorado territorial officials free to pursue violent removal policies.