Final answer:
Southern states were required to repeal secession ordinances, ratify the 13th Amendment abolishing slavery, and adopt new state constitutions that expanded civil rights—including the 14th and 15th Amendments—to be readmitted to the Union.
Step-by-step explanation:
To be considered reconstructed and readmitted to the Union, Southern states had to meet specific requirements set by Congress. States were to hold conventions to repeal the ordinances of secession and ratify the Thirteen Amendment, which abolished slavery. They also had to adopt new state constitutions with various reforms, such as removing property qualifications for voting—leading to universal manhood suffrage, expanding the Bill of Rights, and eliminating distinctions based on color. The states needed to agree to the Fourteenth and Fifteenth Amendments, ensuring citizenship rights and the right to vote would not be denied based on race, color, or previous condition of servitude. These changes marked significant steps towards a more egalitarian society and expanded civil rights post-Civil War.