'Octagon' was the Allied 2nd Quebec Conference, a political and military conference between President Franklin D. Roosevelt and Prime Minister Winston Churchill, each supported by his military advisers (12/16 September 1944).
The primary military topics discussed by the leaders were the future conduct of operations against the Japanese in the Pacific and Burma (with special regard to British participation in the Pacific theatre after the defeat of Germany), and the need to maintain Allied pressure in Italy at least until the end of the 'Gotisch-Linie' battles currently in progress. The main political topic was the disposition of Germany after her military defeat.
So far as Burma operations were concerned, the conference’s directive to Admiral the Lord Louis Mountbatten, the Supreme Allied Commander, South-East Asia Command, ordained that his command’s primary objective was the recapture of Burma and the reopening of land communications with China, to which end 'Capital' was to be implemented as rapidly as possible for the seizure of central Burma with 'Dracula' following by 15 March 1945 to take Rangoon and southern Burma.
With regard to Pacific operations, it was decided that a British Pacific Fleet (with the appropriate fleet train) should be formed and despatched to the region by the beginning of 1945, there coming under the command of Admiral Chester W. Nimitz’s Pacific Fleet in operational matters, and that a fleet of between 600 and 800 heavy bombers ('Tiger' Force) should be sent to the Pacific as soon as possible after the end of operations against Germany.
In Italy, the conference decided, the Allies should await the outcome of the 'Gotisch-Linie' battles, designed to take Field Marshal the Hon. Sir Harold Alexander’s Allied Armies in Italy command across the Apennines to the line of the Adige river, just short of the Piave river, before deciding on what should be attempted next, the US desire being to reduce the strength of Lieutenant General Mark W. Clark’s US 5th Army, while the British plan was still to strengthen the Allied forces with a view to an offensive into Austria and southern Germany.
Perhaps the most important result of 'Octagon' was a pair of early Anglo-US plans for defeated Germany. In the first of these, the country was to be divided into zones of occupation, with the Soviets holding the eastern part of the country, the British the area to the west of the Rhine river and that portion to the east of the river and to the north of a line from Koblenz along the northern borders of Hesse and Nassau, and the Americans the area to the east of the Rhine river and to the south of the line from Koblenz along the northern borders of Hesse and Nassau. The Americans would also control the ports of Bremen and Bremerhaven. Omissions that were later to become a cause of dissent were lack of any French zone, and lack of any plan for joint occupation of Berlin.
The second plan for defeated Germany was the Morgenthau Plan devised by the Secretary of the US Treasury, Henry Morgenthau Jr. This called for the total elimination of German industrial capacity and the expropriation of Germany’s industrial and raw material resources so that the country would be reduced to a subsistence standard of living with an economy based almost entirely on agriculture. Morgenthau’s object was to punish Germany and to prevent the country ever again from developing any war-making capability.
Only extreme pressure from a number of sources prevented this devastating scheme from being presented, in the 'Terminal' conference of July at 1945 at Potsdam, for adoption as standard Allied policy. Even so, the Germans got wind of the proposal, and the propaganda ministry of Dr Joseph Goebbels was able to make great capital out of the Morgenthau scheme which, Goebbels claimed, was designed to punish all Germany and not just the Nazis. The plan also discouraged those anti-Nazi elements in Germany who wished to surrender the country to the Allies as the price of halting a Soviet invasion with all its attendant barbarities.
It was also at the 'Octagon' conference that the Americans decided upon the final stages of the Pacific war against Japan. The 'Strategic Plan for the Defeat of Japan' adopted in the spring of 1943 aimed at the seizure by American forces of the southern coast of China, Formosa and Luzon, where bases could be built for heavy bombers whose attacks would weaken Japan directly and indirectly by cutting the nation’s lines of communication to the 'Southern Resources Area' before the invasion of Japan was attempted. In mid-1944, the strategists is Washington were thinking in terms of bypassing the Philippine islands group to strike directly at Formosa or even the Japanese home islands.
This concept appealed to neither of the commands which were directly involved, namely General Douglas MacArthur’s South-West Pacific Area and Nimitz’s Pacific Ocean Areas, and in July 1944 these two commanders-in-chief met with Roosevelt and his main adviser, Admiral William D. Leahy, in Hawaii to urge that the Philippine islands group should be retained in the overall plan contrary to the desire of Admiral Ernest J. King, the chief of naval operations. Roosevelt was inclined to agree with MacArthur and Nimitz, but nothing definite was decided at this meeting.
During September, however, carrierborne warplanes of Task Force 38, the Fast Carrier Task Force of Admiral William F. Halsey’s 3rd Fleet, raided the southern part of the Philippine islands group and adjacent islands, and found virtually no opposition. Halsey concluded that only small Japanese forces were located in this area, and accordingly suggested to Nimitz that the previous approach to the Philippine islands group via the Yap, Palau and Talau island groups should be replaced by a direct move to the Philippine islands group on Mindanao island or preferably Leyte island farther to the north.
Nimitz agreed with Halsey’s basic concept, though he wanted the 'Stalemate' operation against the Palau islands group to be retained, and forwarded such a recommendation to the Joint Chiefs-of-Staff in Quebec. The Joints Chiefs-of-Staff radioed MacArthur for comment, and received favourable comment in MacArthur’s name from his chief-of-staff, Lieutenant General Richard K. Sutherland, as MacArthur was on board a radio-silenced ship. The Joint Chiefs-of-Staff then decided in favour of 'Stalemate II' for the Palau islands group and 'King II' for Leyte.