Among the groups listed, African Americans and Hispanic Americans gained significant political participation as a result of amendments added to the Constitution.
-
African Americans notably benefited from the 15th Amendment, ratified in 1870, which prohibited denying the right to vote based on race, color, or previous condition of servitude. However, it wasn't fully realized until the Voting Rights Act of 1965, which aimed to eliminate barriers to voting.
-
Hispanic Americans saw increased political participation partly due to civil rights movements and legislation in the 1960s, although no specific Constitutional amendment directly addressed their voting rights.
Asian Americans also gained rights through various legislative changes, particularly the McCarran-Walter Act of 1952, which allowed some Asian immigrants to become U.S. citizens and thereby gain the right to vote, yet this was not through a Constitutional amendment.
Native Americans were granted U.S. citizenship through the Indian Citizenship Act of 1924, but this did not come via a Constitutional amendment.
In conclusion, African Americans are the primary group that gained more political participation directly through the amendments, especially the 15th Amendment, although it took further legislation to ensure those rights were fully protected.