Final answer:
The U.S. historically used a racial caste system based on appearance to dictate social and legal statuses, changing over time with evolving racial classifications and being enforced by laws like Jim Crow, which mandated racial segregation.
Step-by-step explanation:
For the majority of this nation's history, the U.S. has used a racial caste system of racial categorization. This system was rooted in the slave economy of the colonial period and was based on distinctions made largely on appearance or phenotypes. For centuries, these categories regulated social and legal statuses, often in coercive ways.
Racial classifications have been culture and context-specific, evolving over time as exemplified by the US Census Bureau's changing categories. Notably, the United States government also lumped people together by the continent of the origin of their ancestry, such as African-American and Asian-American, despite the problems with such broad categories.
The enforcement of categorization was reinforced through laws like the Jim Crow laws, which established racial segregation and upheld the principle of 'separate but equal'. Although the United States has progressed, traces of the historical racial caste system are still evident in some modern social structures and classifications.