On December 7, 1941, after failing to resolve a dispute with the United States over Japan's actions in China and French Indochina, the Japanese attacked the US Pacific fleet at Pearl Harbor, Hawaii.

The Japanese sought to neutralize the U.S. and Royal navies, seize possessions rich in natural resources, and obtain strategic military bases to defend their far-flung empire.

Anchoring its defensive positions in the South Pacific was the major Japanese army and navy base at Rabaul, New Britain, which had been captured from the Australians in January 1942.

In March 1942 Admiral Ernest King, then Commander-in Chief of the U.S. Fleet, had advocated an offense from New Hebrides through the Solomon Islands to the Bismarck Archipelago.

[6] Following the victory at Midway, General Douglas MacArthur, who had taken command of the South West Pacific Area, proposed a lightning offense to retake Rabaul, which the Japanese were fortifying and using as a base of operations.

These competing proposals were resolved by Admiral King and U.S. Army Chief of Staff General George C. Marshall, who adopted a three-task plan.

Task One, implemented by a directive of the Joint Chiefs of Staff on 2 July 1942 and named the initial attacks Operation Watchtower,[7] became the Solomon Islands campaign.

Operation Cartwheel—the Allied grand strategy for the Solomons and New Guinea campaigns—launched on June 30, 1943, isolated and neutralized Rabaul and destroyed much of Japan's sea and air supremacy.