Page:The U.S. Army campaigns of World War II (IA usarmycampaignso00cent).pdf/7



On 7 December 1941, Japan turned its war on the Asian mainland eastward into the Pacific. Simultaneous attacks on Pearl Harbor, the Philippines, the Malayan peninsula, and other places surprised Allied governments and exposed serious weaknesses in Allied dispositions in the Pacific. At the outbreak of war in Europe in September 1939, Australia had sent most of its ground units to the British Commonwealth Forces in the Middle East. During the next two years the U.S. Pacific Fleet sent one-quarter of its ships to the Atlantic, and the U.S. Army continued mobilizing, although it would not be ready for an offensive mission until late 1942. Hastily gathering scarce units, the Allies tried to halt the Japanese at the Malay Barrier, the mountainous chain of islands stretching from Malaya through the Netherlands East Indies to New Guinea. But the pace and extent of Japanese conquests soon overran these preparations. The fall of Singapore on 15 February 1942 and the bombing of the Australian city of Darwin four days later shattered the Malay Barrier. Australia and New Zealand lay virtually undefended.

The arrival in Australia on 17 March of General Douglas MacArthur, ordered from the Philippines by President Franklin D. Roosevelt, signaled the start of a new phase in the defense of the Pacific. Instead of supplying and supporting its Allies, the United States would commit its own troops to the effort to halt the Japanese. A major area command, Southwest Pacific Area (SWPA), was created in April with General MacArthur commanding. An international command, SWPA had separate land, air, and naval forces, with commanders drawn from the two major contributing nations: Australian General Sir Thomas A. Blamey for Allied Land Forces, American Lt. Gen. George H. Brett for Allied Air Forces, and American Vice Adm. Herbert F. Leary for Allied Naval Forces. Allied Land Forces would consist of two Australian and two American divisions. Recalled from the Middle East, the 7th Australian Infantry Division arrived home at the end of March; the 6th Australian Infantry Division, the next month. Most of the U.S. 41st Infantry Division arrived in