<P> The Axis states which assisted Japan included the authoritarian government of Thailand, which quickly formed a temporary alliance with the Japanese in 1941, as the Japanese forces were already invading the peninsula of southern Thailand . The Phayap Army sent troops to invade and occupy northeastern Burma, which was former Thai territory that had been annexed by Britain much earlier . The official policy of the US government is that Thailand was not an ally of the Axis, and that the United States was not at war with Thailand . The policy of the US government ever since 1945 has been to treat Thailand not as a former enemy, but rather as a country which had been forced into certain actions by Japanese blackmail, before being occupied by Japanese troops . Thailand has been treated by the United States in the same way as such other Axis - occupied countries as Belgium, Czechoslovakia, Denmark, Greece, Norway, Poland, and the Netherlands . </P> <P> Also involved were the Japanese puppet states of Manchukuo and Mengjiang (consisting of most of Manchuria and parts of Inner Mongolia respectively), and the collaborationist Wang Jingwei regime (which controlled the coastal regions of China). In preparation for the war against the United States, which would be decided at sea and in the air, Japan increased its naval budget as well as putting large formations of the Army and its attached air force under navy command . While formerly the IJA consumed the lion's share of the state's military budget due to the secondary role of the IJN in Japan's campaign against China (with a 73 / 27 split in 1940), from 1942 to 1945 there would instead be a roughly 60 / 40 split in funds between the army and the navy . </P> <P> Japan conscripted many soldiers from its colonies of Korea and Formosa (Taiwan). To a small extent, some Vichy French, Indian National Army, and Burmese National Army forces were active in the area of the Pacific War . Collaborationist units from Hong Kong (reformed ex-colonial police), Philippines, Dutch East Indies (the PETA) and Dutch Guinea, British Malaya and British Borneo, Inner Mongolia and former French Indochina (after the overthrow of Vichy French regime) as well as Timorese militia also assisted Japanese war efforts . </P> <P> Germany and Italy both had limited involvement in the Pacific War . The German and the Italian navies operated submarines and raiding ships in the Indian and Pacific Oceans . The Italians had access to "concession territory" naval bases in China, while the Germans did not . After Japan's attack on Pearl Harbor and the subsequent declarations of war, both navies had access to Japanese naval facilities . </P>

When did the us enter the pacific war