Complex sentence: Graff, 206--207 Cleveland believed the Dawes Act would lift Native Americans out of poverty and encourage their assimilation into white society, but its ultimate effect was to weaken the tribal governments and allow individual Indians to sell land and keep the money.
Split into simpler sentences: Graff, 206--207 Cleveland believed the Dawes Act would lift Native Americans out of poverty and encourage their assimilation into white society. It ultimately weakened the tribal governments and allowed individual Indians to sell land and keep the money.