Final answer:
Following the Spanish-American War, the U.S. ruled over Puerto Rico and the island was strategically important for military and commerce reasons. The Foraker Act established its civilian government, and it was only in 1917 that Puerto Ricans were granted U.S. citizenship.
Step-by-step explanation:
Immediately following the Spanish-American War, Puerto Rico was ruled by the United States. The island nation was important to the U.S. because it provided strategic military value in terms of protecting shipping lanes through the Caribbean and the Panama Canal, as well as served as a naval station.
The aftermath of the war saw the Foraker Act of 1900 structure Puerto Rico's civilian government, establishing an organization of the local government and court system, where the U.S. President appointed the governor and upper house members.
Despite its significance, Puerto Rico was labeled an insular area, distinguishing it from incorporated territories which enjoyed full U.S. citizenship rights and paths to statehood. The status of its inhabitants as American citizens wouldn't be recognized until 1917. The island has since maintained its commonwealth status, even after several referendums on its future political status.