Japanese could land hundreds of thousands of troops in the Philippines while American reinforcements, even if they set off from the new naval base being developed at Pearl Harbor on the Hawaiian island of Oahu, would take months. Between these reinforcements and the Philippines lay five thousand miles of ocean, as well as several Japanese-controlled island chains: the Marshalls, the Marianas (save for Guam, which the United States had taken from Spain), and the Carolines.
