Final answer:
During Reconstruction, the Supreme Court's landmark cases, including U.S. v. Reese and U.S. v. Cruikshank, significantly affected the civil rights of African Americans by limiting federal enforcement of the Fourteenth and Fifteenth Amendments and restricting citizenship rights as seen in the Dred Scott decision.
Step-by-step explanation:
The Reconstruction era was a significant period in American history that witnessed numerous Supreme Court cases shaping race relations and the legal status of African Americans. Two crucial cases during this time were U.S. v. Reese and U.S. v. Cruikshank. U.S. v. Reese involved a Kentucky tax collector who tried to prevent black citizens from voting by not collecting their poll tax; this led to the Supreme Court invalidating the First Enforcement Act, as they ruled the Fifteenth Amendment did not apply to local or state elections, only national ones. U.S. v. Cruikshank resulted from an attempt by the government to prosecute individuals involved in the Colfax Massacre; however, the Court decided that the Fourteenth and Fifteenth Amendments only applied to state actions, not individual misconducts, restricting the federal government's power to prosecute for such acts.
Two other notable cases from this era are the Dred Scott v. Sandford decision, which declared that black people could not be citizens of the United States, and the 1883 decision that reversed the Civil Rights Act of 1875, further constraining federal efforts to protect the rights of freed African Americans.