'Trident' was the Allied second Washington conference between President Franklin D. Roosevelt and Prime Minister Winston Churchill, together with their staffs, to confirm earlier decisions and to clarify matters left nebulous at the 'Symbol' conference in Casablanca (15/25 May 1943).

The most important problem facing the conference was the nature of Allied operations in Europe, where the USA wished to pursue as rapidly as possible the development of a direct assault on Germany by means of a cross-Channel operation, and where the UK adhered to the potentially less costly indirect approach through Europe’s 'soft underbelly' with an advance through Italy into Austria and thence southern Germany. Thus the most important single decision of the 'Trident' conference was an Allied commitment to launch a major offensive ('Roundhammer', soon to become 'Overlord') across the English Channel against the German forces in France. The target date was 1 May 1944, and the Allies agreed to have ready some 29 divisions by that date, with facilities for reinforcements to be shipped to France at the rate of three to five divisions per month after the initial lodgement had been secured.

Agreements ancillary to this main undertaking were continued development of 'Sledgehammer' for an emergency return to the continent in the event of a German collapse, and agreement on the so-called Eaker plan of Major General Ira C. Eaker for a four-phase air assault on the Germans in northern Europe (the disruption of the German military, industrial and economic system, the undermining of German morale, the whittling down of German fighter strength, and the ever-deepening penetration of German airspace by Allied aircraft engaged on these tasks).

In exchange for their agreement on the cross-Channel operation, the British won approval from the Americans for continued operations against Italy using forces drawn from a maximum of 27 divisions allocated to the Mediterranean theatre for offensive and garrison duties.

Other agreements were the need to bomb the oil installations at Ploieşti in Romania from North African bases, the urgent requirement to continue the war against the U-boat fleet with all possible strength, and British responsibility for an Allied seizure of the Azores. There was also unanimous reaffirmation of the Casablanca decisions on the desirability of aiding the USSR, of bringing Turkey into the war, and of re-equipping the French forces to carry an increasing proportion of the Allied military load.

The 'Trident' conference was concerned mainly with European matters, but the course of the war against Japan was also discussed, and here the Allies agreed an overall strategy based on a six-phase war considered without time limits and presupposing full co-operation between the Americans, British and Chinese. In the first phase the Chinese would improve their overall position in China, the Americans would open communications into the Celebes Sea, and the British (with US support) would recapture Burma. In the second phase the Americans would recapture the Philippines while the British conducted operations around the Strait of Malacca and the Chinese prepared an offensive toward Hong Kong. In the third phase the Chinese would retake Hong Kong while the British continued with their activities round the Strait of Malacca and the Americans operated in the northern half of the South China Sea. In the fourth phase the three Allied countries would prepare a massive strategic air campaign against Japan from Chinese bases. In the fifth phase this air offensive would be implemented. And in the sixth phase US forces (with British and Chinese assistance) would invade the Japanese home islands.

Within the context of this overall concept, the 'Trident' conference adopted US proposals that air operations in and from China should be increased, that the USA should build up its supply effort to China from India with the aid of operations in northern Burma, that the Japanese should be expelled from the Aleutian islands group, that the Marshall and Caroline island groups should be taken in a major offensive by the forces of Admiral Chester W. Nimitz’s Pacific Ocean Areas command, that the Japanese should be expelled from their last footholds in the Solomon and Bismarck island archipelagos, that the rest of New Guinea should be wrested from the Japanese, and that operations against Japanese lines of communication should be increased in tempo and weight.

At British insistence, it was decided that no major land operations should be undertaken in central and southern Burma, and 'Anakim' was thus postponed.

In the short term, therefore, the 'Trident' conference mandated the continuation of Mediterranean and South-West Pacific Area operations, and the development of major operations in the Central Pacific and minor operations in the North Pacific Area. But most important of all was the longer-term US and British commitment to 'Overlord' and an all-out offensive across North-West Europe.