The first U.S. president to be impeached was Andrew Johnson in 1868. Johnson, who succeeded Abraham Lincoln, faced impeachment primarily due to his violation of the Tenure of Office Act by attempting to remove Edwin M. Stanton, the Secretary of War, from his position. The House of Representatives voted to impeach Johnson, but he was acquitted by the Senate, falling just one vote short of the two-thirds majority needed for removal. Johnson's impeachment highlighted the contentious political climate during Reconstruction and set a precedent for presidential accountability, although it ultimately did not result in his removal.