Puerto Rico is only the latest in a long line of would-be 51st states. Over the past 200 years, there have been several attempts to carve out new states from existing ones, mostly triggered by tax and budget feuds. "South California" tried to split from the more industrialized north in 1859, but Congress said no. In 1861, parts of Tennessee, Georgia, and Alabama attempted to form a neutral state called Nickjack that wouldn't secede from the Union. More recently, rural "South Jersey" tried several times to split from its crowded urban north in the 1970s and 80s [source: Trinklein].
As a commonwealth, Puerto Rico is as close as you can get to being a state without getting a star on the flag. Puerto Ricans are U.S. citizens who pay and receive Social Security benefits. They cannot vote in federal elections and they don't pay federal income taxes. Puerto Rico is in charge of its own internal affairs, but the U.S. controls interstate trade, foreign relations, customs, military service, immigration, agriculture, radio and TV and the postal service.
Now that Puerto Rican citizens passed the referendum on statehood, what are the odds that Congress will take up their cause? Not very good. Although President Obama pledged to take action if Puerto Rican citizens made their preference clear, the political timing is not in Puerto Rico's favor. Puerto Rico suffers from a staggering 45 percent poverty rate -- more than double Mississippi, the current most impoverished state -- and would be entitled to $7.7 billion in federal spending on social programs, Medicaid and more. Since spending cuts are a top congressional priority, this is strike against Puerto Rican statehood [source: Fabian].
Puerto Rico is one of several "unincorporated territories" acquired by the U.S. through war treaties and purchases. In 1901 and 1902, the Supreme Court ruled in the so-called "Insular Cases" to afford limited constitutional rights to unincorporated territories like Puerto Rico and Guam, on the grounds that they would never likely become states [source: Helgesen].
Today, both Guam and the U.S. Virgin Islands share Puerto Rico's odd political status; their residents are U.S. citizens who cannot vote in federal elections. Guam is hoping to hold its own referendum on statehood in 2014, but the U.S. Virgin Islands have no plans for such a vote, known as a plebiscite [source: Sablan]. Puerto Rico has shown the most political interest in statehood, holding four such plebiscites since 1967. In all previous votes, Puerto Ricans opted to remain a U.S. territory [source: Reuters].
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