In the USA, interest in expansion came essentially from a number of practical and ideological changes. First, by virtue of its massive economic growth after the Civil War:- spurred by an abundance of natural resources and rapid industrialization - the United States had become a "great power". Numerous publicists started to suggest that as the United States was now a great power, it should start to act like one.
Practical changes also led to America turning its eye towards other countries. The American "frontier" had essentially disappeared by the last decade of the Nineteenth century; many started to state that the country would need new land and opportunities to serve a growing population. Militarist minds suggested that the US would need to become a great naval nation in order to protect its borders, and Social Darwinists suggested that "manifest destiny" could be extended to other countries. Thus, stated simply, they stated that the world was a jungle and that only the strong in a raw, physical sense could survive. Added to these arguments were those of idealists and religious leaders who argued that Americans should "take up the white man's burden" and carry their supposedly self-evidently superior culture (cultural, economic, political, religious) to the native peoples of the world.
Thus a whole series of factors ...
In 1895 a violent revolution against Spanish rule in Cuba had occurred, set off by an economic depression that had resulted from a decline in American purchases of sugar form the island. Rebel violence was put down violently by the Spanish, and Cuban refugees in the USA started to spread exaggerated and eventually outright fabricated tales of Spanish atrocities.
The power of the print press was partly responsible for the road to war that America now started on. William Randolph Hearst, the great American media baron, whose New York paper The American was in fierce competition with a rival, started to print these stories and to stoke up a jingoistic atmosphere of war. President Cleveland avoided the pressure for war, but his successor, President McKinley was essentially overtaken by events, namely the rather suspicious sinking of the USS Maine on February 15, 1898. The naval board of inquiry claimed that it had been sunk by a Spanish submarine mine, and the resultant loss of life led to war with Spain. Spain offered to make large concessions, but refused to admit what would essentially be defeat - complete withdrawal from Cuba, without a shot fired. In mid April Congress authorized the President to use force to expel the Spanish from Cuba.
Thus started what Secretary of State John Hay expressed in a letter to Theodore Roosevelt was a "splendid little war" for America in which there would be little loss of life, but a massive transformation in international presence (Endicott, 2004). The American expeditionary force quickly routed the Spanish on Cuba and then turned against the last Spanish outpost in the Caribbean, Puerto Rico. In early May the Spanish fleet in Manila, the