Since 1898, Puerto Rico has been an unincorporated territory of the United States. Puerto Ricans are natural born citizens of the United States, yet they can't vote in federal elections, have no voting representatives in Congress, and at any point can have their rights taken away. The island has a population of over 3 million, more than several U.S. states, & a majority of its residents are dissatisfied with its current legal status; however, the federal government has done nothing to alleviate this.
Because of Puerto Rico's questionable legal status, it has been plagued by loads of debt. Tax incentives to get business onto the island failed to give the government the revenue it needed, & now it finds itself severely in debt. It's in the best interest of the U.S. to take action now.