The document summarizes American isolationism and involvement in international affairs from the early 19th century to the post-Cold War era. It discusses key events and doctrines that influenced U.S. foreign policy such as Thomas Jefferson's opposition to foreign entanglements, Manifest Destiny and westward expansion, the Monroe Doctrine, U.S. intervention in Latin America and Asia in the late 19th century, American neutrality and entry into World Wars I and II, the Cold War and space race, and U.S. economic power after the Cold War ended. The document provides historical context on shifting U.S. perspectives from isolationism to global military and economic superpower.