Once again the US House of Representatives has passed a referendum concerning Puerto Rico. Currently the island nation has commonwealth status; which means it's citizens are considered US citizens and can server in the American military but pay no federal income tax on income.
In the past when any referendum has passed in the US legislature, the nation of Puerto Rico has turned the options down. The current referendum if passed in the Senate will offer the citizens of Puerto Rico the choice to change their current status. If Puerto Rico votes for a change then they have the choice of becoming a state, seeking independence, or keeping the current status as a commonwealth.
In the past when given the option of becoming the fifty-first state, Puerto Rico has turned it down. Once reason for this is that many land owners has had their land for generations with no proof of ownership; US statehood would require these citizens to prove such ownership or risk losing the land. Statehood would also require citizens to pay federal income tax, something they do not currently do. Puerto Rico lists Spanish and English as their official languages; becoming a part of the US will require Puerto Rico to follow the US Constitution and possibly change the official language to English only.