Answer:
Under the leadership of President Theodore Roosevelt, the United States emerged from the nineteenth century with ambitious designs on global power through military might, territorial expansion, and economic influence. Though the Spanish-American War had begun under the administration of William McKinley, Roosevelt, the hero of San Juan Hill, Assistant Secretary of the Navy, Vice-President, and President, was arguably the most visible and influential proponent of American imperialism at the turn of the century. Roosevelt’s emphasis on developing the American navy, and on Latin America as a key strategic area of U.S. foreign policy, would have long-term consequences.
In return for Roosevelt’s support of the Republican nominee, William McKinley, in the 1896 presidential election, McKinley appointed Roosevelt as Assistant Secretary of the Navy. The head of the department, John Long, had a competent but lackadaisical managerial style that allowed Roosevelt a great deal of freedom that Roosevelt used to network with such luminaries as military theorists Alfred Thayer Mahan and naval officer George Dewey and politicians such as Henry Cabot Lodge and William Howard Taft. During his tenure he oversaw the construction of new battleships, the implementation of new technology, and laid the groundwork for new shipyards, all with the goal of projecting America’s power across the oceans. Roosevelt wanted to expand American influence. For instance, he advocated for the annexation of Hawaii for several reasons: it was within the American sphere of influence, it would deny Japanese expansion and limit potential threats to the West Coast, it had an excellent port for battleships at Pearl Harbor, and it would act as a fueling station on the way to pivotal markets in Asia.
Teddy Roosevelt on a horse leading charging soldiers up a tropical hill.
Teddy Roosevelt, a politician turned soldier, gained fame (and perhaps infamy) after he and his “Rough Riders” took San Juan Hill. Images like the poster praised Roosevelt and the battle as Americans celebrated this “splendid little war.” “William H. West’s Big Minstrel Jubilee,” 1899. Wikimedia.
Roosevelt, after winning headlines in the war, ran as Vice President under McKinley and rose to the presidency after McKinley’s assassination by the anarchist Leon Czolgosz in 1901. Among his many interventions in American life, Roosevelt acted with vigor to expand the military, naval power especially, to protect and promote American interests abroad. This included the construction of eleven battleships between 1904 and 1907. Alfred Thayer Mahan’s naval theories, described in his The Influence of Sea Power Upon History, influenced Roosevelt a great deal. In contrast to theories that advocated for commerce raiding, coastal defense and small “brown water” ships, the imperative to control the sea required battleships and a “blue water” navy that could engage and win decisive battles with rival fleets. As president, Roosevelt continued the policies he established as Assistant Naval Secretary and expanded the U.S. fleet. The mission of the Great White Fleet, sixteen all-white battleships that sailed around the word between 1907 and 1909, exemplified America’s new power.
Roosevelt insisted that the “big stick” and the persuasive power of the U.S. military could assure U.S. hegemony over strategically important regions in the Western Hemisphere. The United States used military intervention in various circumstances to further its objectives, but it did not have the ability nor the inclination to militarily impose its will on the entirety of South and Central America. The United States therefore more often used informal methods of empire, such as so-called “dollar diplomacy,” to assert dominance over the hemisphere.
The United States actively intervened again and again in Latin America. Throughout his time in office, Roosevelt exerted U.S. control over Cuba (even after it gained formal independence in 1902) and Puerto Rico, and he deployed naval forces to ensure Panama’s independence from Colombia in 1901 in order to acquire a U.S. Canal Zone. Furthermore, Roosevelt pronounced the “Roosevelt Corollary” to the Monroe Doctrine in 1904, proclaiming U.S. police power in the Caribbean. As articulated by President James Monroe in his annual address to Congress in 1823, the United States would treat any military intervention in Latin America by a European power as a threat to American security. Roosevelt reaffirmed the Monroe Doctrine and expanded it by declaring that the U.S. had the right to preemptive action through intervention in any Latin American nation in order to correct administrative and fiscal deficiencies.