There were many reasons why the Harlem Renaissance held such significance in US history despite its fading influence during the Great Depression, but the main reasons is because it introduced whites to black culture.
Due process is the legal concept that all citizens will be treated equally in terms of the law. This can be seen in the US Constitution with the 5th and 14th amendments. Here is an example: If a person is arrested for committing a crime, they must have their rights read to them. Once this person is arrested and read their rights, they are entitled to a trail with a jury of their peers present. The aforementioned rights are ones that ALL citizens are entitled to, no matter who you are.
The key foreign policy issues that America had to face during the 1800´s were: to protect United States ships; and to deal with pirates.