How have industrial changes military conflicts the great depression, and civil unrest shaped the american century?

Military conflict in the american century led to the emergence of the USA as the world sole superpower,but essentially degenerated into nuclear threat.
   The American society emerged from the great depression stronger economically,but more essentially an economy that cared for the welfare of its people as established by the new deal.
The civil unrest of the 1800s created a more homogenous democratic society.
quick paced industrialised saw the usa emerge as the economic powerhouse of the world.