Final answer:
The 13th, 14th, and 15th Amendments abolished slavery, granted citizenship and equal protection under the law to African Americans, and granted them the right to vote, thereby integrating them into the nation's political and social sphere.
Step-by-step explanation:
The 13th, 14th, and 15th Amendments to the U.S. Constitution were significant landmarks in the liberation and inclusion of African Americans in the nation's political and social sphere. The 13th Amendment ended the institution of slavery, granting freedom to a large African American population that had lived in bondage. This amendment was revolutionary; however, to ensure the complete inclusion of newly freed people, further amendments were required.
The 14th Amendment granted citizenship rights to all African Americans, providing equal protection under the law. It dismantled the Supreme Court's 1857 Dred Scott decision, which had stated that African Americans could never be citizens. This amendment was an important barrier against overtly racially discriminatory laws.
Building upon these foundations, the 15th Amendment was ratified. This amendment ensured that the right to vote would not be denied or abridged based on race, color, or previous condition of servitude, essentially giving African American men the right to vote. This final step could be seen as the point at which African Americans gained formal political power in the United States.
Learn more about Civil War Amendments