Complex sentence: Most of the leadership believed that the reservation system should go and the Indian Bureau abolished, but differences of opinion arose over when and how this was to be achieved and what relationship the non-reservation Indian should have it to the reservation.
Split into simpler sentences: Most of the leadership believed that the reservation system should go and the Indian Bureau abolished. But differences of opinion arose over when and how this was to be achieved and what relationship the non-reservation Indian should have it to the reservation.