After Lincoln´s assassination, Andrew Johnson became the president on April 15, 1865. After a couple of months, Johnson started executing his plan for the South's reconstruction. When the Congress met to assess the situation there was outrage. One of the assumptions that lead to the conclusion that president Johnson was overstepping his boundaries was fueled by most Republicans who thought the reconstruction of the South was the job of Congress and the Congress alone.
The Congress created a plan to distribute the land amongst freedmen and create schools for their children but this bill was vetoed by the president who found it extremely expensive and unconstitutional. There was clear disagreement between the President and the Congress. After further debate and the establishment of several bills from the Congress to address the afterwar issues, the government crisis came to a climax. The Congress passed another bill to restrict the president from firing anyone from his cabinet without previous authorization from the Senate, a decision that was automatically rejected by Johnson who stated this was a violation to the separation of powers, these were the assumptions that led to both conclusions.