Answer:
What led African Americans to be treated as slaves in President Johnson's reconstruction plan were the "black codes."
Step-by-step explanation:
Johnson continued to rebuild the former Confederate States while Congress was in recess. When Congress met in December 1865, slavery was being abolished. But the "black codes," which regulated the freed slaves, were beginning to appear.
Radical Republicans in Congress, alarmed at the restrictions placed on blacks, have moved to change Johnson's program. Refusing to accept any congressman or senator from the former Confederacy, they approved measures aimed at former slaves. Johnson vetoed the legislation. Congress overturned its veto and passed the Civil Rights Act of 1866, establishing blacks as US citizens and prohibiting any discrimination against them.