Indian Peace Commission: all Plains Indians to move to two large reservations
Demand for buffalo increased through the 1800s and habitat was lost to white Americans who were eager for land. The increase in hunting in conjunction with habitat loss led to near extinction of the buffalo population. The Native Americans who were heavily reliant on the buffalo were severely impacted by this massive drop in their main food source.
November 1864 - The Sand Creek Massacre - 133 Native Americans killed by a (presumably drunken) volunteer militia force led by Colonel J.M. Chivington
but I thought we were under protection
1876 - The Battle of Little Bighorn - tribal warriors surprised and killed Custer & his 264 man regiment
we have you surrounded
"Indian Hunting" was widespread in the west, especially since bounties tended to be offered for dead Natives.
I am going to kill you and make a lot of money
The Ghost Dance was a religious revival movement that spread among Natives in the US. It was associated with Wovoka's prophecy to bring an end to white expansion; it likely contributed to Native American resistance.