In my view the period that has had the biggest impact on the development of US society is The Great Depression. That depression brought a huge economic growth but also changed mass culture that swept many Americans into consumer society.
Answer:
Many government officials felt that Native Americans should be assimilated into America's mainstream culture before they became enfranchised. The Dawes Act of 1887 was passed to help spur assimilation. It provided for the dissolution of Native American tribes as legal entities and the distribution of tribal lands among individual members (capped at 160 acres per head of family, 80 acres per adult single person) with remaining lands declared "surplus" and offered to non-Indian homesteaders. Among other things, it established Indian schools where Native American children were instructed in not only reading and writing, but also the social and domestic customs of white America.
The Dawes Act had a disastrous effect on many tribes, destroying traditional culture and society as well as causing the loss of as much as two-thirds of tribal land. The failure of the Dawes Act led to change in U.S. policy toward Native Americans. The drive to assimilate gave way to a more hands-off policy of allowing Native Americans the choice of either enfranchisement or self-government.
Military leader with the real power in Japanese government (instead of the Emperor). This system was established by Minamoto Yoritomo as part of the Bakufu. Military style government set up by Yoritomo Minamoto in which the Shogun, a military leader, is in charge of the government.
