Secretary of War in Abraham Lincoln's cabinet during the Civil War, Edwin M. Stanton was known for his ability and energy. He also possessed an abrasive personality. Stanton became Lincoln's chief cabinet advisor and a major link to the Republican congressional leaders. Prior to that service he was active in the Democratic Party and attorney general under Pres. James Buchanan. Following Lincoln's death, and the succession of Andrew Johnson to the presidency, Stanton continued in his War Department post. In a dispute with Johnson over policy surrounding the reconstruction of the South, Stanton was removed from office. He challenged the move through the new Tenure of Office Act and was returned to his office when the Senate refused to concur with the President's action.