1. The focus was on expansionism, the United States took little part in foreign affairs for much of the 1800s. Committed to the policy of isolationism, the U.S. declined to intervene in an independence movement in Poland when asked to do so by foreign leaders.
2. For Turner, continental expansion, symbolized by the ever moving frontier creating more free land, was the driving, dynamic factor of American progress and Mahan of the U.S. Navy had no qualms about moving the frontier beyond the coastline.
3. European nations set up colonies in Asia and Africa to acquire raw materials and sell their goods in new markets. In the late 1800s and early 1900s, Americans also started to focus on colonial expansion. New economic and political pressures encouraged this move toward imperialism.