An explosion sank the battleship USS Maine in Havana Harbor, killing more than 260 U.S. sailors. The incident sharply escalated U.S.–Spain tensions and helped propel the United States toward war.
Congress adopted the Teller Amendment as part of the war resolution against Spain, declaring that the United States would not annex Cuba and would leave control of the island to its people after pacification.
Congress declared war against Spain, formalizing the Spanish–American War and setting in motion U.S. military operations in the Caribbean and Pacific that would lead to overseas acquisitions.
Commodore George Dewey’s Asiatic Squadron destroyed Spain’s Pacific Squadron at Manila Bay. The victory enabled U.S. occupation of Manila and made the Philippines central to ensuing peace negotiations.
U.S. forces took Guam in a largely bloodless action, beginning U.S. control of the strategically located island in the Marianas during the war’s Pacific campaign.
U.S. forces captured key heights near Santiago de Cuba in a major land victory that helped force Spain’s surrender of Santiago and hastened the war’s end.
Congress passed the Newlands Resolution, annexing the Republic of Hawaii. Although separate from Spain’s empire, annexation in 1898 was closely tied to wartime strategy and Pacific expansion.
U.S. forces began the Puerto Rico campaign by landing at Guánica on the island’s southern coast, opening the path to U.S. occupation and, later, formal cession under the peace treaty.
The United States and Spain signed a peace protocol that suspended hostilities and set terms to negotiate a final treaty, paving the way for territorial transfers.
The Treaty of Paris was signed, ending the war. Spain relinquished sovereignty over Cuba and ceded Puerto Rico and Guam to the United States; the United States acquired the Philippines under the treaty’s terms.
Clashes around Manila on February 4–5 marked the opening of the Philippine–American War, as Filipino forces resisted continued U.S. rule following the U.S. decision to retain the Philippines.
The U.S. Senate ratified the Treaty of Paris by a narrow margin, securing U.S. claims to Spain’s ceded territories and intensifying domestic debates over imperial expansion.
With the exchange of ratifications, the Treaty of Paris became effective, legally implementing Spain’s cessions and changing the status of acquired territories under U.S. law and administration.
The United States, Germany, and Great Britain signed the Tripartite Convention, ending the shared arrangement in Samoa and assigning the eastern islands (including Tutuila) to U.S. control—an additional step in U.S. overseas expansion during the same era.
President McKinley appointed the Second Philippine Commission (Taft Commission) to establish civil governance in U.S.-controlled areas of the Philippines, signaling a transition from purely military administration to civil rule.
The Foraker Act (Organic Act of 1900) replaced U.S. military rule in Puerto Rico with a U.S.-controlled civilian government structure, defining the island’s early political relationship with the United States after cession.
The Platt Amendment set conditions for U.S. troop withdrawal from Cuba and constrained Cuba’s treaty-making and fiscal sovereignty, formalizing U.S. influence over Cuban affairs after the war.
In a series of decisions decided the same day (including DeLima v. Bidwell and Downes v. Bidwell), the Supreme Court addressed how the Constitution and tariff laws applied to newly acquired territories, shaping the doctrine of U.S. unincorporated territories.
Spanish–American War and U.S. Overseas Acquisitions (1898–1901)
