The period immediately following the Civil War is known as Reconstruction. The broken, split nation had to be "reconstructed". President Lincoln had a plan. The Radical Republicans in Congress had a plan. They clashed.
Lincoln believed..
His primary goal was to restore the Union ASAP. Reinstate Southern representation in Congress quickly.
13th - Abolished slavery
14th - Freed slaves granted citizenship. Bill of Rights protections now extend to them. Guarantees "equal protection of the law". Gives the Federal government some power to place more restrictions on state governments.
15th - Voting rights (suffrage) for African-American men. The South responded to this amendment by adding Literacy Tests and Poll Taxes to keep blacks from voting (disenfranchisement).
Laws that were written to restrict freedom and rights of African-Americans.
Northerners who moved down south to participate in the Reconstruction government.
African-American were not allowed to raise their own crops (Black Codes). Sharecropping gave them the opportunity to work farms owned by landlords for hefty payments (usually half their crops) Merchants supplied the sharecroppers with tools, seeds, clothing, food, etc. in exchange for large payments. Some sharecroppers made a living working on the farms of their farmers owners in exchange for some of the profits.
Often violent group started by ex-Confederate soldiers that used fear and violence to intimidate African-Americans and "meddling" northern carpetbaggers.
Tested the 14th amendment. The court ruled that "separate but equal IS equal". The court allowed racial segregation as long as the separate facilities were "equal". They weren't. This decision led to the passage of Jim Crow laws.