Planning For The Battle of Iwo Jima - American Planning

American Planning

The origins of the battle lie in the complex politics of the Pacific theater, in which operational control was divided between the South West Pacific Area (command) of General Douglas MacArthur and the Pacific Ocean Areas (command) led by Admiral Chester Nimitz. The potential for interservice rivalry between the Army and Navy created by this partition of responsibility was exacerbated by similar divisions within the Joint Chiefs of Staff (JCS) in Washington. By September 1944, the two services could not come to an agreement about the main direction of advance towards the Japanese home islands in the coming year. The Army was pressing for the chief effort to be an invasion of Formosa (Taiwan), in which MacArthur would be in overall command and in which it would predominate.

The Navy however preferred the idea of an operation against Okinawa, which would be a mainly seaborne effort. Seeking to gain leverage and so break the impasse, on September 29 Nimitz suggested to Admiral Ernest King that as a preliminary to the Okinawa offensive the island of Iwo Jima could be taken. The tiny island lacked harbors and so was of no direct interest to the Navy, but for some time General Henry Harley Arnold of the U.S. Army Air Forces had been lobbying to take Iwo Jima. He argued that an airbase there would provide useful fighter escort cover for the B-29 Superfortresses of his XX Bomber Command, then beginning its strategic bombing campaign against the Japanese home islands (the later role of Iwo Jima as a refueling station for B-29s played no part in the original decision-making process). Arnold's support in the JCS enabled the Navy to get Okinawa rather than Formosa approved as the main target on October 2. At this time the Iwo Jima invasion was expected to be a brief prologue to the main campaign, with relatively light casualties; King assumed that Nimitz would be able to reuse three of the Marine Corps divisions assigned to Iwo Jima for the attack on Okinawa, which was originally scheduled to take place just forty days later.

On 7 October 1944, Admiral Chester Nimitz and his staff issued a staff study for preliminary planning, which clearly listed the objectives of Operation Detachment. The overriding purpose of the operation was to maintain unremitting military pressure against Japan and to extend American control over the Western Pacific. Three tasks specifically envisioned in the study were the reduction of enemy naval and air strength and industrial facilities in the home islands; the destruction of Japanese naval and air strength in the Bonin Islands, and the capture, occupation, and subsequent defense of Iwo Jima, which was to be developed into an air base. Nimitz's directive declared that "long range bombers should be provided with fighter support at the earliest practicable time", and as such Iwo Jima was "admirably situated as a fighter base for supporting long range bombers."

On 9 October, General Holland Smith received the staff study, accompanied by a directive from Admiral Nimitz ordering the seizure of Iwo Jima. This directive designated specific commanders for the operation. Admiral Raymond A. Spruance, Commander, Fifth Fleet, was placed in charge as Operation Commander, Task Force 50. Under Spruance, Vice Admiral Richmond Kelly Turner, Commander, Amphibious Forces, Pacific, was to command the Joint Expeditionary Force, Task Force 51. Second in command of the Joint Expeditionary Force was Rear Admiral Harry W. Hill. General Holland Smith was designated Commanding General, Expeditionary Troops, Task Force 56.

It was not accidental that these men were selected to command an operation of such vital importance that it has since become known as "the most classical amphibious assault of recorded history." All of them had shown their mettle in previous engagements. One chronicler of the Iwo Jima operation put it in the following words:

"The team assigned to Iwo Jima was superb: the very men who had perfected the amphibious techniques from the Battle of Guadalcanal to the Battle of Guam. Nearly every problem, it was believed, had been met and mastered along the way, from the jungles of Guadalcanal up through the Solomons, and across the Central Pacific from the bloody reefs of Battle of Tarawa to the mountains of the Marianas."