Legislature of Guam

During the Spanish colonial era, lasting roughly from the 1670s until 1898, Guam was provided with no colonial legislature. All political decisions on the island were left to a Madrid appointed governor, who, until 1817, reported to the Viceroy of New Spain in Mexico. Due to New Spain's distance from Guam and the speed of transportation of the times, Guam's leadership often took matters into its own hands. During the Mexican War of Independence, when Spain increasingly saw New Spain falling through its grip, Madrid transferred Guam's political authority to the Governor of Manila, and after 1821, fully to the Spanish Philippines.

Spain lost Guam during the 1898 Spanish–American War in a bloodless invasion. For the next forty years, the United States Navy assumed executive control of the island, treating it more as a military outpost than an overseas territory, with little to no civilian say in the island's affairs. Governor Captain Willis Winter Bradley instituted the Guam Congress during the 1930s as an elected advisory body to the naval governor. On December 8, 1941, Imperial Japanese forces invaded Guam, beginning a three-year occupation of the island. The island was eventually retaken in 1944 during the intense Battle of Guam.

Following the end of the war, the U.S. Navy attempted to resume military control of the islands, much to the dismay of the local Chamorro population who demanded greater rights on the heels of the harsh Japanese occupation. The U.S. federal government listened. The result was the Guam Organic Act of 1950 signed by President Harry S. Truman. The act established a civilian territorial government with executive, legislative, and judicial branches. It was the first time that Guam had a democratic civilian government.