Australia in early April. The U.S. 32d Infantry Division, originally slated for Northern Ireland, received new orders to join SWPA in mid-May with the rest of the 41st Division. Allied Air Forces would eventually consist of eight aircraft groups. Allied Naval Forces began with twenty-one surface warships and thirty-one submarines and could expect augmentation by American carrier task forces. Resupply of the Southwest Pacific Area would come from Hawaii through a line of island bases secured in February: Palmyra, Christmas Island, anton Island, Bora Bora, Samoa, and the Fiji Islands.
Working with the Australian Chiefs of Staff, General MacArthur prepared a joint estimate of the situation. The Allies agreed that the Japanese advance would continue and that it would soon threaten the Australian supply line as well as the island nation itself. As General MacArthur viewed the situation, the best way to defend Australia was to meet the Japanese on New Guinea, and the way into New Guinea lay through Port Moresby, a harbor on the southeast Papuan coast lightly garrisoned by Australians. Accordingly, in early April MacArthur directed the reinforcement of Port Moresby.
While the Allies rushed to strengthen Port Moresby, the Japanese acted on their own strategic assessment. They also considered Port Moresby the key to Australia. But before approaching the port city, the Japanese moved to finish a naval mission begun earlier. The Imperial Japanese Navy saw its strike against Pearl Harbor as only half of a two-part strategy. To secure exploitation of Burma, Malaya, and the Indies, the Japanese had to neutralize the British Eastern Fleet. For that purpose, a large Japanese naval task force left the southwest Pacific for the Indian Ocean in April. The Japanese succeeded in disabling the British Eastern Fleet, but in doing so they also gave SWPA an extra month to reinforce Port Moresby.
By 4 May, when a Japanese landing force embarked at Rabaul for Port Moresby, Allied air and naval forces had grown to decisive strength. The result for the Japanese was a major setback. As enemy troopships and an escorting carrier task force approached the eastern end of New Guinea, they were met by two American carrier task forces. In the ensuing Battle of the Coral Sea, the Japanese Navy lost so many ships that the landing force had to return to Rabaul. Though they lost more ships than the Japanese, the Allies won a strategic victory in the Coral Sea: the enemy had to reschedule its Port Moresby landing for July.
The Japanese had barely counted their losses in the Coral Sea when they met a much more costly defeat. In an effort to take Midway Island and the Aleutians, the Imperial Japanese Navy put to-
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