The impeachment of Andrew Johnson, the 17th President of the United States, occurred in 1868. It was primarily driven by political conflicts following the Civil War, particularly over the Reconstruction policies. Johnson's violation of the Tenure of Office Act, which restricted the president's power to remove certain officeholders without Senate approval, led to his impeachment by the House of Representatives. The Senate trial resulted in Johnson being acquitted by just one vote, preventing his removal from office. This impeachment marked a significant moment in U.S. history, highlighting the tensions between the presidency and Congress during the Reconstruction era.