A private letter by Spain’s minister in Washington, Enrique Dupuy de Lôme, insulting President William McKinley was published in the U.S. press, inflaming American public opinion during the Cuba crisis and adding momentum toward war.
The U.S. battleship USS Maine exploded in Havana Harbor, killing over 260 crew members. The disaster became a major catalyst for U.S. intervention in Cuba and escalation toward war with Spain.
President McKinley signed the joint resolution demanding Spain relinquish control of Cuba; the attached Teller Amendment disclaimed any U.S. intention to annex Cuba, shaping U.S. war aims and postwar policy debates.
The U.S. formally declared war on Spain, marking the start of open hostilities in what became the Spanish–American War and accelerating U.S. military operations in the Caribbean and Pacific.
Commodore George Dewey’s Asiatic Squadron defeated Spain’s Pacific fleet at Manila Bay, giving the U.S. decisive naval control in the Philippines and enabling subsequent U.S. occupation operations around Manila.
Emilio Aguinaldo issued the Philippine Declaration of Independence from Spain. The declaration, and subsequent revolutionary governance, set up a sovereignty conflict once the U.S. moved from defeating Spain to retaining the Philippines.
U.S. naval forces took Guam in a largely bloodless operation, extending U.S. control in the western Pacific and foreshadowing broader U.S. overseas territorial acquisitions in 1898.
U.S. forces attacked key Spanish positions in eastern Cuba, including actions at El Caney and the assault on San Juan Heights (including San Juan Hill). The victories tightened the siege of Santiago and helped force Spain’s collapse in Cuba.
Spain’s attempt to break out of Santiago harbor ended in the destruction of its squadron, eliminating Spain’s major naval presence in the Caribbean and strongly reinforcing U.S. bargaining power in the peace settlement.
U.S. forces began major land operations in Puerto Rico by landing at Guánica, opening a campaign that ended quickly once the August armistice took effect and Puerto Rico was transferred under the peace terms.
A protocol signed in Washington, D.C., halted hostilities and set the framework for a formal peace treaty: Spain would relinquish Cuba, cede Puerto Rico and an island in the Ladrones, and the U.S. would occupy Manila pending final disposition of the Philippines.
U.S. forces took Manila after a prearranged “mock battle” with Spanish authorities, designed to avoid surrendering the capital to Filipino revolutionary forces and to secure a U.S. occupation position before final peace terms.
Spain and the United States signed the Treaty of Paris: Spain renounced sovereignty over Cuba and ceded Puerto Rico, Guam, and the Philippines to the United States (with the U.S. agreeing to pay $20 million for the Philippines).
President McKinley directed U.S. military authorities to extend U.S. control over the Philippines under a policy framed as “benevolent assimilation,” intensifying the sovereignty dispute with Filipino revolutionaries after the Spanish–American War.
Clashes in Manila escalated into the Battle of Manila (February 4–5, 1899), widely treated as the opening major engagement of the Philippine–American War—an armed conflict closely linked to the U.S. decision to annex the Philippines after 1898.
The U.S. Senate narrowly ratified the Treaty of Paris, making U.S. acquisition of Spain’s former overseas territories legally effective and cementing a major shift toward U.S. overseas empire.
Congress enacted the Foraker Act to replace U.S. military rule in Puerto Rico with a civilian (insular) government, defining the island’s political administration under U.S. sovereignty after the 1898 transfer.
The Platt Amendment set conditions for ending the U.S. military occupation of Cuba and constrained Cuban foreign policy while authorizing U.S. intervention; Cuba incorporated its terms into its 1901 constitution as a condition of U.S. withdrawal.
Spanish–American War and the United States' Overseas Expansion (1898–1901)
