Final answer:
The Chief allowed the Sioux to focus on tradition in the 1880-1890's with the Ghost Dance.
Step-by-step explanation:
The person who allowed the Sioux to focus on tradition in the 1880-1890's with the Ghost Dance was the Chief.
During this time, Sioux tribal leaders such as Sitting Bull and Crazy Horse rejected assimilation and revived traditions like the Ghost Dance, which was a spiritual movement that offered hope for the restoration of their lands and way of life.
The Ghost Dance was seen as a way to resist assimilation and preserve Sioux traditions and culture.