why did conflict erupt between President Johnson in Congress after Lincoln's assassination?

There were several reasons for the conflict between President Johnson and Congress after Lincoln's assassination:

1. Different visions for Reconstruction: Johnson's Reconstruction plan was lenient towards the South, while Congress wanted to impose harsher penalties and ensure civil rights for African Americans.

2. Disagreements over the 13th, 14th, and 15th Amendments: Johnson opposed these amendments, which abolished slavery, granted citizenship to African Americans, and gave them the right to vote.

3. Removal of Edwin M. Stanton: Johnson attempted to remove Stanton, the Secretary of War, without the approval of Congress. This violated the newly passed Tenure of Office Act, which required Senate approval for such removals.

4. Impeachment: In response to these conflicts, Congress impeached Johnson in 1868 for violating the Tenure of Office Act. Although he was acquitted by the Senate, this further strained relations between the executive and legislative branches.