In what ways is it helpful to view World War II as a series of overlapping regional conflicts that finally built into a genuine global war following the formal entry of the United States in December 1941? To what extent had the United States succeeded in establishing global hegemony and a new U.S.-led world system by 1945?

In what ways is it helpful to view World War II as a series of overlapping regional conflicts that finally built into a genuine global war following the formal entry of the United States in December 1941? To what extent had the United States succeeded in establishing global hegemony and a new U.S.-led world system by 1945?