In which case, policy, or situation did the motto “kill the indian, but save the man” play an important role in western expansion?

C the boarding schools. They took Native children and sent them to boarding schools where they were forbidden to speak their own language or be their own culture. The kids were brought up "white" and taught to feel shame about where they came from. This was successful in that those kids are able to survive in the "white" world, some went to college, they learned work ethic, etc. They had no foundation in their culture though, and have no idea what to teach their children about who they are or what their ancestors learned. This has led to all kinds of trouble with Native peoples, this not knowing or being ashamed of their culture.