Answer:
The philosophy drove 19th-century U.S. territorial expansion and was used to justify the forced removal of Native Americans and other groups from their homes. The rapid expansion of the United States intensified the issue of slavery as new states were added to the Union, leading to the outbreak of the Civil War.
Historians describe white Southerners' varied responses to emancipation and the issue of civil rights, and describe the thinking that gave rise to white supremacist groups like the Ku Klux Klan during Reconstruction.
