President Barack Obama dangles U.S. dollars before the Castros while Congress stonewalls Puerto Rico's pleas for debt restructuring. The Tampa Bay Rays take the field in Havana as San Juan fends off New York hedge funds wielding legal baseball bats. The Rolling Stones play a free concert for Cubans; Puerto Rico can't get no satisfaction.

As Cuba rises and Puerto Rico falls, it's worth considering the diverging trajectories of these two ex-Spanish colonies that the Puerto Rican poet Lola Rodriguez de Tio described more than 100 years ago as "two wings of the same bird." Even as the resumption of diplomatic ties with the U.S. opens new possibilities for Cuba, Puerto Rico's current status as a U.S. commonwealth has turned into an ugly dead end.

Puerto Rico is defaulting in slow motion on $70 billion worth of debt. Its economy has shrunk nine of the past 10 years. A few hundred kilometers to the west, meanwhile, economic reforms are creating new livelihoods for self-employed Cubans, whose material conditions are improving. Buoyed by the arrival of new tourists, remittances, and foreign investments, Cuba's economy grew by 4 percent last year.