Japan launches a surprise attack on the United States Pacific fleet at Pearl Harbor, Hawaii, severely damaging the fleet. The attack prevents, at least for the short term, serious American interference with Japanese military operations.
In response to the attack, the United States declared war on Japan. Following Germany's declaration of war on the United States, the United States also declared war on Germany. After the attack on Pearl Harbor, Japan attacked and occupied Guam, Wake, the Philippines, the Dutch East Indies, Hong Kong, Malaya, Singapore, and Burma. Only in mid-1942 were Australian and New Zealander forces in New Guinea and British forces in India able to halt the Japanese advance. But the turning point in the Pacific war came with the American naval victory in the Battle of Midway in June 1942. The Japanese fleet sustained heavy losses and was turned back. Allied forces slowly gained naval and air supremacy in the Pacific.