In 1898, following the Spanish-American War, the United States acquired several territories, most notably Puerto Rico and Guam.

The war marked a significant shift in U.S. foreign policy, leading to its emergence as a global power. Puerto Rico became a U.S. territory, and its residents were granted U.S. citizenship in 1917. Guam, also acquired in the treaty, remains a U.S. territory today. Additionally, the war facilitated the later acquisition of the Philippines, illustrating America's imperial ambitions and the complex legacy of its involvement in the Caribbean and Pacific regions.