Final answer:
The problem that persisted even after the Congressional Reconstruction was racial discrimination and injustice faced by black Americans.
Step-by-step explanation:
The problem that persisted even after the Congressional Reconstruction was racial discrimination and injustice faced by black Americans. Despite the efforts to guarantee black rights, racism and violence were pervasive in the South. Most black southerners continued to work as tenants or sharecroppers while being subjected to public segregation and voting discrimination. The effects of slavery endured long after emancipation.