As "Russkaya Germaniya" notes, the current complex status of Puerto Rico means that the island is under U.S. administration without being an integral part of the country. The U.S. Constitution applies to the island only partially, supreme authority belongs to the U.S. Congress, but the island has its own constitution and system of self-government.
The Puerto Rico Status Commission was established back in 2000 by order of President Bill Clinton. It recommended granting the island's citizens the right to self-determination. Since then, several referendums have been held, two in 2012 and one in 2017. But while six years ago 65% of voters supported turning Puerto Rico into the 51st state of the U.S., in 2017 that figure was already 97%.
Earlier, representatives of the Republican Party stated that they would not allow changing Puerto Rico's status, and the U.S. Department of Justice even spoke out against holding this referendum. Nevertheless, among the congressmen who introduced the bill to grant statehood to the island were representatives of both the Republican and Democratic parties.
If the bill is passed, Puerto Rico's admission as a U.S. state is expected to be completed by 2021.
• The last time new states joined the U.S. was in 1959, when Alaska and Hawaii were admitted. Currently, besides Puerto Rico, there is a campaign to grant statehood to the federal District of Columbia. In a 2016 referendum, 80% of residents voted for turning the district into a state.
The project to change the administrative status assumes that, although Columbia would become a state, a federal district would remain on its territory where government structures would be located.
The main reason for the status change is the desire of the residents. Members of the U.S. Congress are elected only from states, and residents of the District of Columbia currently have no representation there. Meanwhile, the district's population is 600,000, which is larger than that of some states. In 1993, a bill to change Columbia's status was rejected in Congress, but the district continued its struggle.