Johnson suspended Stanton after disagreements related to Reconstruction and replaced him with General of the Army Ulysses S. Grant on an interim basis. After clashing with Grant, Johnson offered the position of Secretary of War to General William T. Sherman, who declined, and to Lorenzo Thomas, who accepted. Thomas never took office; Johnson appointed John Schofield as Secretary of War as a compromise with moderate Republicans. Johnson thus became the first U.S. president to be impeached by Congress. Ulysses S. Grant emerged as the likely Republican presidential candidate during the two years preceding the election. Though he had agreed to replace Stanton as Secretary of War, Grant split with Johnson over Reconstruction and other issues.