Explain the social, economic, and political impact of westward expansion on the development of the United States and its people from the establishment of the Republic in 1787 to the beginning of the Civil War. What were the major acquisitions of new territory? When, how and why did they happen? What changes in the social, economic and political development of the country did they generate? How did they contribute to growing divisions within the American identity and the eventual coming of the Civil War? As always, be explicit in your arguments and support them with specific examples.