Bureau of Insular Affairs in the context of "Insular Government of Porto Rico"

The Insular Cases are a series of opinions by the Supreme Court of the United States in 1901 about the status of U.S. territories acquired in the Spanish–American War. Some scholars include cases regarding territorial status decided up until 1914, and others include related cases as late as 1979.The term "insular" signifies that the territories were islands administered by the War Department's Bureau of Insular Affairs. Today, the categorizations and implications put forth by the Insular Cases still govern the United States' territories.

When the war ended in 1898, the United States had to answer the question of whether or not people in newly acquired territories were citizens, a question the country had never faced before. The preliminary answer came from a series of Supreme Court rulings, now known as the Insular Cases, which responded to the question of how American constitutional rights apply to those in United States territories. The Supreme Court held that full constitutional protection of rights does not automatically (or ex proprio vigore—i.e., of its own force) extend to all places under American control. This meant that inhabitants of unincorporated territories such as Puerto Rico—"even if they are U.S. citizens"—may lack some constitutional rights (e.g., the right to remain part of the United States in case of de-annexation) because they were not part of the United States. Today, many legal scholars such as José Julián Álvarez González, Christina Burnett, and others refer to the Insular Cases as a constitutional justification for colonialism and annexation of places not within United States boundaries. The Insular Cases "authorized the colonial regime created by Congress, which allowed the United States to continue its administration—and exploitation—of the territories acquired from Spain after the Spanish–American War." These Supreme Court rulings allowed for the United States government to extend unilateral power over these newly acquired territories.

Title 48 of the United States Code outlines the role of United States territories and insular areas in the United States Code.

• Chapter 1: Bureau of Insular Affairs
• Chapter 2: Alaska
• Chapter 3: Hawaii
• Chapter 4: Puerto Rico
• Chapter 5: Philippine Islands
• Chapter 6: Panama Canal Zone
• Chapter 7: Virgin Islands
• Chapter 8: Guano Islands
• Chapter 8a: Guam
• Chapter 9: Samoa, Tutuila, Manua, Swains Island, and Trust Territory of the Pacific Islands
• Chapter 10: Territorial Provisions of a General Nature
• Chapter 11: Alien Owners of Land
• Chapter 12: Virgin Islands
• Chapter 13: Eastern Samoa
• Chapter 14: Trust Territory of the Pacific Islands
• Chapter 15: Conveyance of Submerged Lands to Territories
• Chapter 16: Delegates to Congress
• Chapter 17: Northern Mariana Islands
• Chapter 18: Micronesia, Marshall Islands, and Palau
• Chapter 19: Pacific Policy Reports
• Chapter 20: PROMESA