Among the groups listed, African Americans gained significant political participation through amendments to the Constitution. Key amendments include the 15th Amendment, which granted African American men the right to vote, and the 19th Amendment, which expanded voting rights to women.
While other groups, such as Native Americans, also gained rights over time, it was primarily through a combination of amendments and later legislation (such as the Indian Citizenship Act of 1924) that their political participation was affected. Therefore, for the context of constitutional amendments specifically, the most direct impact was on African Americans.