Expansion overseas was not a completely innovative idea seeing as the Monroe Doctrine (Issued in 1823 when Latin countries were revolting for independence) considered Latin America in the United States' sphere of influence. A State Department list, the "Instances of the Use of United States Armed Forces Abroad 1798-1945," recorded a quantity of 103 interventions of affairs of other countries between the years of 1798 and 1895. This showed that the use had ample experience in overseas investigation and interventions.
Alfred T. Mahan, the Captain of the U.S. Navy, regarded as a popular propagandist for expansion, greatly influenced Theodore Roosevelt and other American leaders. Mahan thought that the country with the most powerful navy would inherit the earth. He believed we should build a canal, and to protect the canal by controlling Hawaii and Cuba, which he thought was a necessity.
During this time, thoughts of Anglo-Saxon superiority were a common "excuse" for imperialism. The political scientist and professor of Columbia University, John Burgess said the Teutonic and Anglo-Saxon races were "particularly endowed with the capacity for establishing national states… they are entrusted… with the mission of conducting the political civilization of the modern world." Even before McKinley's presidency, he exhibited interest in foreign markets for the surplus of American products. This later on became an important when McKinley became president.
On eve of expansionism during Roosevelt's presidency, people thought it was a matter of manliness and heroism, but he was conscious of "trade relations with China." In 1898, 90% of American products were sold at home; the 10% sold abroad amounted to a billion dollars. By the year of 1893, American trade exceeded that of every country in the world except England. The Farming, Steel, and Oil industries relied heavily on