The focus of U.S. territorial expansion shifted from the Atlantic to the Pacific starting in the 1790s, reflecting a desire for growth and opportunity linked to manifest destiny.
The U.S. engaged in complex negotiations and conflicts with several nations, including Mexico (Mexican-American War), Spain (through various military and political maneuvers), and England (involving treaties like the Oregon Treaty and the eventual border settlements).
The interaction with Native American tribes was marked by treaties, forced removals, and conflicts, notably culminating in the end of the Indian Wars with the massacre at Wounded Knee in 1890.
By the late 19th century, particularly following the closure of the frontier, the U.S. began its transformation into a global power through a series of imperial policies and military engagements.
The Industrial Revolution prompted a significant increase in U.S. manufacturing, driving the need for expanded markets abroad and access to essential raw materials.
This economic expansion was characterized by a surge in U.S. exports, particularly in industries like steel, textiles, and agriculture, leading to economic ties with countries in Asia and Latin America.
There was a prevailing desire for the U.S. to compete on the global stage, particularly with European powers and Japan, leading to a race for dominance in Africa and Asia.
Political ideologies supporting nationalism and globalism gained traction, encouraging expansion as a means of demonstrating strength and power.
The strategic need for military bases to protect U.S. interests and secure trade routes became increasingly important, especially in the context of naval power and global shipping lanes.
Influential naval strategist Alfred Thayer Mahan emphasized the significance of a strong navy and control of key maritime locations, which influenced U.S. policies around the Panama Canal and other strategic points.
Ideologies like Social Darwinism, which suggested that stronger nations had a right to dominate weaker ones, were used to justify imperialist actions.
Concepts such as the "white man’s burden," popularized by figures like Rudyard Kipling, rationalized imperial expansion as a moral duty to civilize non-Western peoples.
American missionaries began arriving in Hawaii in the 1820s, aiming to convert the native Hawaiian population to Christianity, while American business interests in sugar and pineapple plantations flourished. This led to significant land acquisition efforts spearheaded by families like the Doles.
Queen Liliuokalani’s efforts to restore sovereignty to Hawaii led to conflict with pro-annexation factions within the islands. A revolt initiated by American plantation owners resulted in her overthrow in January 1893.
Although President Grover Cleveland initially opposed the annexation in 1893, citing respect for Hawaiian sovereignty, Hawaii was ultimately annexed in 1898 under President William McKinley following the strategic interests of the U.S.
The struggle for Cuban independence from Spain, marked by leaders such as José Martí, gained significant attention and spurred U.S. involvement due to substantial investments in Cuban sugar plantations.
The use of yellow journalism heightened public sentiment against Spain, fueled by sensationalized reports of atrocities committed against Cubans. This was further exacerbated by the De Lôme letter, which criticized President McKinley.
The explosion of the USS Maine in Havana Harbor in February 1898 served as the immediate catalyst for the declaration of war against Spain.
The war was declared in April 1898, leading to swift U.S. victories in Cuba and the Philippines, notably the Battle of San Juan Hill.
The Treaty of Paris, signed in December 1898, concluded the conflict, granting the U.S. territories, including Guam, Puerto Rico, and the Philippines.
The formation of the Anti-Imperialist League, which included prominent figures such as Andrew Carnegie and Mark Twain, criticized the annexation of new territories, raising concerns over governance, rights for inhabitants, and the implications of empire.
In Cuba, the Platt Amendment was introduced, altering previous agreements by allowing U.S. intervention in Cuban affairs and establishing Guantanamo Bay as a naval base.
Puerto Rico was granted limited self-rule, with citizenship extended in 1917, though debates about its status and rights as a U.S. territory persisted.
In the Philippines, brutal guerrilla warfare erupted as American forces sought to suppress independence movements led by Emilio Aguinaldo, resulting in thousands of deaths and significant conflict.
The U.S. adopted an Open Door Policy in 1899, introduced by Secretary of State John Hay, aimed at ensuring equal trade opportunities for all nations in China amid growing foreign influence.
The Boxer Rebellion (1899-1901) was a nationalist uprising against foreign control and intervention in China, which was ultimately suppressed by an international coalition, including U.S. troops, reinforcing American involvement in Asian affairs.
Roosevelt adopted a much more interventionist foreign policy using his mantra "speak softly and carry a big stick," advocating for U.S. involvement in global affairs.
Roosevelt secretly supported the Panamanian independence movement from Colombia in 1903 after Colombia refused U.S. offers to build a canal. The construction of the Panama Canal, completed in 1914, was vital for trade and military movement.
Roosevelt’s policy extension of the Monroe Doctrine asserted the U.S. right to intervene in Latin American countries to prevent European intervention, leading to military interventions in several nations, including Haiti, Honduras, the Dominican Republic, and Nicaragua.
Roosevelt played a key role in mediating the end of the Russo-Japanese War, for which he was awarded the Nobel Peace Prize, highlighting U.S. influence in international diplomacy.
The Gentlemen’s Agreement of 1907 was a compromise that restricted Japanese immigration to the U.S. while addressing racial discrimination in California, signifying an attempt to ease tensions between the nations.
The "Great White Fleet," a fleet of U.S. Navy ships, was deployed globally to showcase American naval power and diplomatic strength.
The policies advanced by Presidents McKinley and Roosevelt set the stage for a more aggressive U.S. foreign policy in the early 20th century, influencing the approaches of subsequent presidents, including Taft and Wilson, and establishing a legacy of American involvement in global affairs.