In June 1943, the Joint Chiefs of Staff directed Admiral Chester W. Nimitz, Commander in Chief of the Pacific Fleet (CINCPAC), to submit a plan to occupy the Marshall Islands. Initially both Nimitz and Admiral Ernest J. King, the Chief of Naval Operations, wanted to attack right into the heart of the Japanese outer defense perimeter, but any plan for assaulting the Marshalls directly from Pearl Harbor would have required more troops and transports than the Pacific Fleet had at the time. Considering these drawbacks and the limited combat experience of the U.S. forces, King and Nimitz decided to take the Marshalls in a step-by-step operation via the Ellice and Gilbert Islands. The Gilberts lay within of the Southern Marshalls and were well within range of United States Army Air Forces B-24 aircraft based in the Ellice Islands, which could provide bombing support and long-range reconnaissance for operations in the Gilberts. With those advantages in mind, on 20 July 1943 the joint Chiefs of Staff decided to capture the Tarawa and Abemama atolls in the Gilberts, plus nearby Nauru Island. The operation was codenamed "Operation Galvanic."