Final answer:
Three Supreme Court decisions, U.S. v. Reese, U.S. v. Cruikshank, and the Court's ruling on the Enforcement Acts, weakened the goals and operation of Reconstruction by limiting the impact of the 14th and 15th Amendments.
Step-by-step explanation:
Three Supreme Court decisions that seriously weakened the goals and operations of Reconstruction were U.S. v. Reese, U.S. v. Cruikshank, and the Court's ruling on the Enforcement Acts.
These decisions served to limit the impact of the 14th and 15th Amendments.