Under the sudden attack of Japan, Britain and the United States suffered setbacks on the Pacific battlefield, and the vast areas of the Western Pacific to be defended before the war and at the beginning of the war were successively occupied, such as Hong Kong, Singapore, British Malaya, part of Myanmar, the Philippines, Dutch East India, New Britain, New Ireland and most of New Guinea Solomon Islands and a range of other Pacific Islands.

Australia, New Zealand, the Hawaiian Islands, Ceylon and India are threatened.

The strategic frontier of the United States in the Pacific has retreated to the arc centered on Hawaii, north to the Aleutian Islands and south to Australia.

If this line of defense is also broken, the west coast of the United States will be exposed to the Japanese army.

On March 9, 1942, on the day of the Japanese occupation of Java, the president of the United States telegraphed the British Prime Minister that the situation in the Pacific is now very serious.

According to President Roosevelt’s proposal, on March 17, the heads of state of Britain and the United States reached an agreement on the division of the strategic zone.

Britain is responsible for the Middle East and the Indian Ocean (including Malaya and Sumatra), while the United States is responsible for the whole Pacific (including Australia and New Zealand).

India and Myanmar are in the strategic area under the responsibility of Britain, while the Chinese theater is under the responsibility of the United States.

At the same time, the two sides further confirmed the basic strategy of “Europe before Asia”.

This means that the United States should take a strategic defensive stance in the Pacific.

However, the rapidly deteriorating situation has led to a wave of public opinion in the United States calling for revising the strategic policy of “Europe before Asia” and paying attention to the Pacific battlefield.

The Joint Chiefs of staff of the United States convened from February to 16, 1943.

At the meeting, the U.S. Navy strongly advocated turning the main force of the U.S. Army and navy to the Pacific battlefield, launching a joint offensive, driving the Japanese out of Rabaul, lifting the threat to Australia, and even using reinforcements sent to Europe for this purpose.

The opinion of the army aviation force is diametrically opposite.

It demands to go all out to defeat Germany in Europe, does not advocate sending reinforcements to the Pacific, and is prepared to bear the consequences of losing Australia.

Finally, according to the policy of sticking to Australia and New Zealand and launching an attack in the Pacific announced by President Roosevelt at the White House meeting on March 5, the Joint Chiefs of staff adopted the compromise strategic plan put forward by the Army Department, and decided to ensure that the Pacific side can undertake the current task on the premise of adhering to the basic strategy of “Europe before Asia”, Send limited troops to protect the security of Hawaii and Australia.

As Admiral Kim said, the strategic policy of the United States in the Pacific is: “abide by the code and attack if you can.

” In this way, while training troops and accumulating materials for large-scale attacks in Europe and Africa, the United States also provides a large number of ships, aircraft and troops for the Pacific theater, so as to stick to important positions and defend traffic lines there.

In order to implement the above strategic plan, the United States has established a new command system in the Pacific theater.

According to the resolution of the Joint Chiefs of staff approved by President Roosevelt on March 30, 1942, the Pacific battlefield is divided into two main theater: the southwest Pacific theater and the Pacific theater.

The southwest theater includes Australia and its adjacent waters, the western Solomon Islands, the islands, New Guinea, the Philippines and Dutch East India (except Sumatra).

The US Army General was appointed commander in chief of the southwest Pacific theater, with the headquarters in Melbourne.

On July 20, 1942, the headquarters moved to Brisbane, Australia.

The rest of the Pacific region is under the jurisdiction of the Pacific theater, except for the area near the Panama Canal and the coastal area of South America West of longitude 110 degrees.

Due to the vast sea area, the Pacific theater is divided into three regions: the North Pacific region, the central Pacific region and the South Pacific region.

Admiral Nimitz, commander of the US Pacific Fleet, served as the commander in chief of the Pacific theater, under the leadership of admiral Kim, commander in chief of the US Navy, while MacArthur was under the leadership of General Marshall, chief of staff of the US Army.

In March 1942, MacArthur and Nimitz were instructed by the US Joint Chiefs of staff to clarify the operational tasks of the two theaters.

The directive stipulates that the task of the southwest Pacific theater is to hold Australia’s key military area and use it as a base to prevent the Japanese army from conquering the southwest Pacific and counterattack against Japan in the future.

Smash the Japanese attack on Australia and its main transportation lines, destroy the Japanese troops, supply ships, aircraft and bases entering New Guinea, Bismarck islands and Solomon Islands, and prevent the Japanese attack.

Eliminate Japanese ships transporting raw materials to Japan from the newly conquered areas and impose an economic blockade on Japan.

Defend land, sea and air supply lines in the southwest Pacific and its surrounding areas.

Garrison troops on the islands along the southwest Pacific and establish bases to ensure the safety of air routes in the region.

Support friendly forces in the Pacific and Indian oceans.

Prepare for a counterattack.

The United States Joint Chiefs of staff stipulates that the task of the Pacific theater is to ensure the transportation supply line between the United States and the southwest Pacific and the islands necessary for operations.

Support friendly forces in the southwest Pacific.

Contain the Japanese army in the Pacific.

Support the defense of the North American continent.

Defend important sea and air traffic supply lines.

Prepare to carry out a large-scale landing war on the Japanese military base.

The initial offensive should be launched in the South Pacific and southwest Pacific.

As can be seen from the above series of strategic decisions and tasks, by March 1942, the United States had abandoned the Philippines and the Western Pacific, retreated to the central Pacific and the southwest Pacific, and tried to defend the vast area from Aleutian Hawaii Australia to the west coast of the United States on the basis of the Pacific on the defensive.

Among them, the focus is to hold the two strategic points of Hawaii and Australia, as well as the long maritime traffic line connecting the two places, so as to form a solid strategic frontier of defense against Japan.

The mission undertaken by the US Southwest Pacific theater is mainly defensive.

In terms of how to complete the main task of defending Australia, it faces two choices: one is the inland defense plan envisaged by Australia, that is, to establish an Adelaide defense line from Brisbane to the south coast in the southeast of Australia, so as to protect the heart of Australia.

Second, the overseas defense plan advocated by MacArthur, commander of the southwest Pacific theater.

MacArthur believes that the inland defense plan will sacrifice the vast northwest of Australia, which is a pure negative defense.

Even if we hold this line of defense, the result will be that the US Army will be trapped by the Japanese army indefinitely.