Franklin D. Roosevelt implemented a strategy in two theaters.
Franklin D. Roosevelt . During his first 100 days in office , Roosevelt spearheaded unprecedented federal legislation and issued a profusion of executive orders that instituted the New Deal -- a variety of programs designed to produce relief ( government jobs for the unemployed ) , recovery ( economic growth ) , and reform ( through regulation of Wall Street , banks and transportation ) . As an active military leader , Roosevelt implemented a war strategy on two fronts that ended in the defeat of the Axis Powers , and he initiated the development of the world 's first atomic bomb .