Because the Tenure of Office Act did permit the president to suspend such officials when Congress was out of session, when Johnson failed to obtain Stanton's resignation, he instead suspended Stanton on August 5, 1867, which gave him the opportunity to appoint General Ulysses S. Grant, then serving as Commanding General of the Army, interim secretary of war. When the Senate adopted a resolution of non-concurrence with Stanton's dismissal in December 1867, Grant told Johnson he was going to resign, fearing punitive legal action. Johnson assured Grant that he would assume all responsibility in the matter, and asked him to delay his resignation until a suitable replacement could be found. Contrary to Johnson's belief that Grant had agreed to remain in office, when the Senate voted and reinstated Stanton in January 1868, Grant immediately resigned, before the president had an opportunity to appoint a replacement. Johnson was furious at Grant, accusing him of lying during a stormy cabinet meeting. The March 1868 publication of several angry messages between Johnson and Grant led to a complete break between the two. As a result of these letters, Grant solidified his standing as the front-runner for the 1868 Republican presidential nomination.