The War Department's original plan was to attack the main force on Kiska Island, but it took Kinkaid's suggestion to bypass Kiska in favor of an assault on the less heavily defended Attu Island. Kinkaid moved his headquarters to Adak to be with those of Buckner and Butler, and at Buckner's suggestion established a joint mess where their two staffs ate meals together. However, the amphibious planning was done in San Diego by Rockwell and his U.S. Marine Corps advisor, Brigadier General Holland M. Smith. The Battle of Attu was only the third American amphibious operation of the war, and was carried through to a costly success under difficult conditions. The slow rate of progress ashore caused Kinkaid to relieve the Army commander, Major General Albert E. Brown and replace him with Major General Eugene M. Landrum. In June 1943, Kinkaid was promoted to vice admiral, thereby removing any lingering doubts about who was in charge, and awarded his third Distinguished Service Medal. He now prepared Operation Cottage, the much larger invasion of Kiska. This was carried out as planned, but the invaders found that the Japanese had already evacuated the islands. In September 1943, Kinkaid was replaced by Vice Admiral Frank Fletcher.