The years following the Civil War were the years of great economic expansion in the history of the United States. As industries increased production, the demand for resources rapidly increased, and since the lands under US control could not meet this demand, the only option was to expand the land area. In 1867 the United States purchased Alaska from Russia and annexed the Midway Islands that same year. Until the 1890s expansion was limited to the west and did not cross the nation's borders. But the 1890s, the period between 1893 and 1903, was a turning point in U.S. history, marked by America's expansion outside its mainland for the first time. Although politicians justified imperial expansion with the doctrine of manifest destiny, other causes, notably the Depression of 1893, strategic military acquisition to enhance U.S. security, international competition, and the need to control more of the world in order to become the world power, effectively encouraging the United States to expand beyond its borders. This changed the traditional American foreign policy from isolationist to interventionist, which involved America in various international disputes at the risk of its own security. After 1865, facilitated by the development and expansion of railroads, American industries grew rapidly and pushed production beyond domestic demands. This progress attracted immigrants from around the world rapidly increasing the population of the United States. This increase in population, wealth and industrial production required more resources and, with America already expanding towards the West, the only option was to explore areas outside the national borders… middle of the paper… D along with this responsibility comes a threat, a threat against his own people. Works Cited • Graebner, Norman A. Foundations of American Foreign Policy. Wilmington, Scholarly Resources Inc., 1985• McKinley, William. “President McKinley on the American Empire.” Voices of Freedom: A Documentary History, edited by Eric Foner—3rd ed. New York: W. W. Norton & Company, 2011• Jayne, Madison M., An American Time Capsule: Three Centuries of Broadsides and Other Published Ephemera, “Imperialism Defined and Demonstrated,” September 8, 1900.http://memory.loc. gov/cgibin/ampage?collId=rbpe&fileName=rbpe08/rbpe085/0850170c/rbpe0850170c.db&recNum=0&itemLink=D?rbpebib:1:./temp/~ammem_Id14::@@@mdb=manz,mharendt,rbpebib,cwband,cwny h ,gmd,mreynoldsbib,mtaft,cwar,fsaall,mfdipbib,mff,scsmbib,mal,mcc,ncpm,pan,afcpearl,lhbprbib,afc911bib,papr,runyon,detr,mgw,nfor,sgp,sgproto,ww2map&linkText=0