Puerto Rico has been discussed as a potential 51st state of the United States. In a 2012 status referendum a majority of voters, 54%, expressed dissatisfaction with the current political relationship. In a separate question, 61% of voters supported statehood (excluding the 26% of voters who left this question blank). On December 11, 2012, Puerto Rico's legislature resolved to request that the President and the U.S. Congress act on the results, end the current form of territorial status and begin the process of admitting Puerto Rico to the Union as a state.

What country has been regarded as a potential new addition to the United States?