Yes if u wonna be american before this the sign was magna carta
During the American revolution, the Patriots side was heaviliy outnumbered by The British. On top of that, the patriot's weapons were also inferior.
In such a desperate moment, the patriots decided to obtain any help that they can, by opening an opportunity for African Americans (from both northern and southern sides) to join the Revolution army in order to achieve freedom from the British.
A democracy works under meeting and exercise the government in person, while a republic is the meeting and agreements of the citizens. They assemble and administrate to keep the discussion civil.
It was primarily during the 1870s that the US government passed all of the Indian Appropriation Acts, since prior to this time the US was mostly concerned with issues revolving around the Civil War.