In the twelve years of his presidency, Franklin D. Roosevelt delivered only 30 fireside chats. He used radio strategically, to avoid becoming frequent enough to be written-off or ignored. As World War II unfolded in Europe, German forces occupied or threatened most of the continent and Japan dominated the South Pacific, driving American forces down the Bataan peninsula. FDR used the radio to explain the War Americans, often encouraging his listeners to follow along on a map to better understand the events he described. Historians argue that FDR used his radio program strategically to gain public support for U.S. entry into WWII, which had initially been an overwhelmingly unpopular proposition.