evidence: On December 7, 1941, Japan staged a surprise attack on Pearl Harbor, severely damaging the US Pacific Fleet. When Germany and Italy declared war on the United States days later, America found itself in a global war. Japan launched a relentless assault that swept through the US territories of Guam, Wake Island, and the Philippines, as well as British-controlled Hong Kong, Malaya, and Burma. Yet, with much of the US fleet destroyed and a nation unprepared for war, America and its allies decided they needed to save Great Britain and defeat Germany first.