Final answer:
Ulysses S. Grant and some of his contemporaries viewed Native American tribes as a threat, exacerbated by their Civil War alliances and conflicts with federal troops. Meanwhile, nativism grew against new immigrants, leading to laws limiting immigration based on ethnic and religious backgrounds. Figures like Frederick Douglass opposed these views, arguing for the value of American diversity.
Step-by-step explanation:
President Ulysses S. Grant recognized the dishonorable nature of the nation's dealings with Native American tribes but saw no alternative to the reservation system despite occasional expressions of regret. His military colleagues often saw Native Americans through a lens tainted by their alliance with the Confederacy during the Civil War and by incidents of violence. This became a pretext for justifying policies toward Native tribes, which were often viewed as remnants of a defeated enemy and a threat to American security.
Simultaneously, nativist sentiments in the U.S. led to a desire to prevent immigration of those seen as different from a white, Anglo-Saxon, Protestant ideal, leading to a backlash against new immigrants from Central and Southern Europe, Asians, and other minorities. This resulted in movements and legislation aimed at curbing immigration, like the Chinese Exclusion Act, and later, quota acts that greatly reduced the number of immigrants allowed from certain countries.
The underlying fear was that the newcomers would endanger the moral and social fabric of American society, despite counterarguments by leaders like Frederick Douglass, who championed America's diversity as a strength and advocated for the rights of all individuals, regardless of their ethnic background.